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CeraNews
ISSUE 1/2015

The Orthopedic Landscape Information Journal

©©Galina Barskaya (Bücher); Denis (Knie) / fotolia

Focus: K
nee Arthroplasty
Evidence-based Medicine in Orthopedics

www.ceranews.com

TABLE OF CONTENTS

Guest Commentary

Benazzo F, MD, Pavia, Italy

Focus: Knee

Future of Knee Endoprosthetics:
Ceramic Components find their Place

Interview with Mittelmeier W, MD, Rostock, Germany

Clinical Cases: Primary Knee Arthroplasty in
Patients with Suspected or Confirmed Metal Allergy

Benazzo F, Pavia, Italy

Focus: Evidence

Evidence-based Decision-Making and
Biological Reactions Related to Materials
Usbeck S, Scheuber LF, Plochingen, Germany

Science

Mid-term Results of Modern Ceramic-on-Ceramic
Total Hip Arthroplasty

Laforgia R, Bari, Italy

2015 Update on an Evolving Perspective for
Taper Corrosion in Total Hip Arthroplasty

Kurtz SM, Philadelphia, USA

Science Report

Fretting and Corrosion
Discussion of Methods for Assessment and Testing

Pandorf T, Plochingen, Germany

Science

Does Bearing Influence Septic Loosening of
primary Total Hip Arthroplasty?

Bordini B, Bologna, Italy

Pauwels Commemorative Medal 2014

Materials Research

The Effect of Chromia Content on Hardness of
Zirconia Platelet Toughened Alumina Composites

Kuntz M, Plochingen, Germany

Science Report

What´s New in Endoprosthetics in Russia?

Tikhilov RM, St. Petersburg, Russia

Tribology: Science and Practice in Korea

Zimmermann M, Graessel M, Plochingen, Germany

28
30

News Ticker

Heinz-Mittelmeier Research Award

Congresses & Workshops

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CeraNews 1/ 2015

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GUEST COMMENTARY

Total Knee Arthroplasty is currently Experiencing
a New Phase
By Benazzo F, MD, Pavia, Italy

he number of prostheses implanted worldwide every year is constantly increasing for several reasons:

• more surgeons are being educated to perform this particular class of operation;
•m
ore patients now have a longer life span and increased articular damage as a consequence of
the extended utilization of their joints;
• e xtension of the indications for TKA in a range of young, active patients with damaged knees,
• and implants are becoming more easily available in emerging countries.
Together with the growing number of surgeries, an increased incidence of related problems is also
becoming evident, including:
• r esidual symptoms in a high percentage of patients (almost 20 %), such as pain, stiffness, and
instability, along with other minor but annoying symptoms;
• material-related problems such as wear in young and active patients; and allergies.
Thus, it is evident that efforts must be made to improve designs (with a strong shift toward more
natural kinematics of the knee), materials (that are not harmful for the patients and have a long and
wear-free life), and techniques and methods of implantation (robotics). There is also new interest being shown in partial prosthetic replacement of the affected knee (uni-compartmental, bi-unicondylar,
patellofemoral joint replacement).
The Biolox®delta composite ceramics, owing to their manufacturing features such as bending
strength and stress load capacity, could be the new benchmark of biomaterials available for clinical
use, as demonstrated by the cohort of patients treated with knee devices made of Biolox®delta. New
scenarios are therefore opening, specifically in the so-called small-implants field of partial knee replacement.
However, the safety and reliability of new implant products for patients must be guaranteed. No longer can we allow the success of a device to be validated on the basis of biased, by definition, expert
opinion. All the new phases of applied research entail the problem of demonstrating efficacy and
safety, clearly and incontrovertibly. Therefore, they must be validated under the umbrella of the evidence-based medicine (EBM). The evidence pyramid should be the basis for evaluating the properties
and quality of any device, material, or surgical method. Critical evaluation has received enhanced attention with metal-on-metal (MoM) failure and consequent clinically devastating effects, such as adverse reactions to metal debris (ARMD). Critical evaluation has been extended to the “new” materials
such as cross-linked polyethylene (XPE), (for which the claimed lack of wear was not demonstrated),
and to new phenomena, such as corrosion of the metal junction in all prosthetic designs.
Together with the awareness of the potential drawbacks that any innovation could bring, and of the
harm any patient could suffer, research on new applications of proven materials such as Biolox®delta
ceramics will continue and will be monitored in accordance with the EBM principle.
This is the message that the new issue of CeraNews wants to bring to the customers.

Francesco Benazzo, MD

CeraNews 1/ 2015

GUEST COMMENTARY

Francesco M. Benazzo, MD, studied medicine at the University of Pavia,
graduating in 1980. He devoted himself to electron microscopy during his
studies and early in his career. He pioneered the application of special techniques such as freeze-etching and freeze-fracture to the connective tissue,
and in particular to cartilage and tendons.
He trained as an orthopedic surgeon in Pavia, completing his education in orthopedics and traumatology in 1985 with a thesis on a rare genetic disease
involving the long bones (Lipomembranous osteodystrophy), including an
electron microscopic evaluation of the lesions. During the residency program,
he was introduced by his mentor, Prof. Boni, both to cervical spine surgery
and to sports traumatology.
Benazzo served as assistant in the Sports Traumatology Section of the orthopedic clinic and finally assumed an academic position as assistant professor in 1990. In 2000 he became full professor of orthopedics and traumatology, and two years later Chairman of the Orthopedic and Traumatology Department of the University of Pavia, San Matteo Hospital. Since then, he has also chaired the Program of
Residency in Orthopedics and Traumatology. In 2002, he became consultant to the Football Club Internazionale Milano, where he served until 2014 as surgeon.
His main fields of scientific and clinical interest are connective tissue structure and mechanics, tendinopathies in athletes and functional overload injuries, spinal osteoarthritis, cementing techniques, hip
and knee prosthetic surgery, the development of MIS surgical techniques and tools for total knee replacement, and tissue engineering with the use of SAOS-2 and stem cells.
In 2005, Benazzo became President of the EFOST (European Federation of National Associations of Orthopedic Sports Traumatology). He is a member of IRCS (International Cartilage Repair Society), of ISAKOS (International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine), and of the
European Hip Society, and secretary and member of the Italian College of Professors of Orthopedics
and Traumatology.
He designed 3 different hip stems, and one knee prosthesis. Benazzo has been a visiting surgeon (Australia, France, South Korea) and an instructor on cadavers for total knee arthroplasty and unicompartimental replacement.

ACRONYMS

CeraNews 1/ 2015

AAOS

American Academy of Orthopaedic Surgeons

HHS

Harris Hip Score

ARMD

Adverse Reactions to Metallic Debris

HOOS

Hip dysfunction and Osteoarthitis Outcome Score

ASTM

American Society for Testing and Materials

Hazard Ratio

BMI

Body Mass Index

Hardness Vickers

Co Cobalt

KSS

Knee Society Score

CoC Ceramic-on-Ceramic

LTT

Lymphocyte Transformation Test

CoCr Cobalt-Chromium

MoM Metal-on-Metal

CoCrMo Cobalt-Chromium-Molybdenum

MoP Metal-on-Polyethylene

CoP Ceramic-on-Polyethylene

OKS

Cr Chromium

PE Polyethylene

Oxford Knee Score

RoM

Range of Motion

DGOOC Deutsche Gesellschaft für Orthopädie und Orthopädische
Chirurgie (German Society of Orthopedics and Orthopedic
Surgery)

SCC

Squamous Cell Carcinoma

SF-12®

Short Form, Health Survey Score

DGU

German Association for Trauma Surgery

THA

Total Hip Arthroplasty

EBM

Evidence-Based Medicine

TJA

Total Joint Arthroplasty

EFORT

European Federation of Orthopaedics and Traumatology

TKA

Total Knee Arthroplasty

EHS

European Hip Society

XPE

Crosslinked Polyethylene

FDA

Food and Drug Administration

ZTA

Zirconia Toughened Alumina

Computer Tomography

The Future of Knee Endoprosthetics:
Ceramic Components Find Their Place

Interview with Wolfram Mittelmeier, MD, Rostock, Germany

Whereas ceramic materials have already been accepted in hip arthroplasty, knee arthroplasties
are still frequently carried out using MoP bearings. However, there are some good arguments
in favor of using ceramic knee components: For example, in patients with known allergies or
where replacements are required as a result of septic loosening, Prof. Mittelmeier recommends
full ceramic or ceramic coated components. The modern alumina matrix composite ceramics
demonstrate enhanced bending strength and stress-load capacity and are therefore appropriate
even for the kinematically demanding artificial knee. Current 5-year data from a European multicenter study verify that a Biolox®delta ceramic femur condyle shows stable fixation and convincing durability.

Why is a knee TEP patient so often dissatisfied?
Mittelmeier: The frequency of patients’ dissatisfaction is higher in knee endoprosthetics than in
hip endoprosthetics. This is very likely due above all
to the highly complex kinematics of the knee joint
and to the kinematically more demanding operative
technique. There is also probably a certain connection with the metal/polyethylene procedure, which
is still being carried out, while ceramic components
are the gold standard in hip endoprosthetics.
In hip endoprosthetics the problem of metal
abrasion, corrosion, and fretting with modular prostheses is currently under intensive discussion, and the use of ceramic-on-ceramic or
ceramic-on-polyethylene is suggested. Do you
think this will also be an issue in knee endoprosthetics?
Mittelmeier: The initial euphoria regarding the use
of metal in hip endoprosthetics has given way to
disillusionment in recent years. In particular, large
metal/metal bearings have been the target of criticism because of pronounced granulomas and increased incidents of early loosening. These problems
of metal ions and metal abrasion apply equally to
knee endoprosthetics, whereby the larger joint volume with greater capsule surfaces probably constitutes a higher level of tolerance, however. Never
theless, the long-term application of knee endoprostheses with the well-known increase in allergy
problems in our population makes it reasonable to
expect similar problems, although probably not of
the same magnitude.
For which patients would you choose a ceramic prosthesis rather than a metal prosthesis?

Mittelmeier: If an allergy is known and a ceramic solution is available appropriate to the kinematics, I would favour it. Since no such kinematically
perfected ceramic solution is available for revisions,
improved ceramic coatings must be considered as
an alternative. I would also advise that these ceramic-coated knee components be used for patients who require a septic revision of their endoprosthesis and have been treated with intermittent
cement spacer. In these cases there is an accumulation of zirconium oxide particles in the normal
bone cement, which cannot be reliably removed by
joint lavage even with the most intensive efforts.
Are there differences in the follow-up care of
ceramic and metal implants?
Mittelmeier: No.
Do you see any clinical differences between
all-ceramic and ceramic-coated knee components?
Mittelmeier: In this regard we have carried out and
published a retrospective study (comparison of cohorts) comparing a particular coated, older type of
knee with our ceramic components [1]. These differences are almost impossible to document in shortterm clinical trials, but in some cases there is slightly increased abrasion with coated components, at
least for the type of implant studied by us. In the
long term, however, I would expect to see a significant advantage for the ceramic monoblock solution,
because the thin coatings on the market to date are
subject to constant abrasion and their wearing out
is foreseeable. Newer multiple coatings could yield
better results, but they must still be tested in clinical practice.
CeraNews 1/ 2015

INTERVIEW

What must be taken into consideration when
a ceramic component is implanted?
Mittelmeier: The alumina matrix composite (Bio
lox®delta), from which the current knee components – Multigen Plus Ceramic Knee (Limacorporate S.p.A.)
(Fig. 1), BPK-S ceramic knee (Peter
Brehm GmbH) – are manufactured, demonstrate
considerably greater bending strength and stressload capacity. Nonetheless, as with every material, a certain maximum load limit remains. The ce-

Figure 1: Multigen Plus delta C
eramic Knee (Limacorporate)

ramic components should be inserted without a socalled wedge load and thus without a strong press
fit. Hammer blows should be used very cautiously, analogous to proven practice for ceramic heads
in hip arthroplasty.* Likewise, the saw cuts in the
knee joint must be precisely executed. It should be
noted that we now know to what extent a strong
press fit situation and sharp blows on metal components lead to internal stress with possible consequential damage. In the past few years we have
learned to be even more careful with all of our implants, particularly with all instruments.
What is your experience with the Multigen
Plus Ceramic Knee following 5 years of clinical use?
Mittelmeier: We began to introduce the Delta
Ceramic Knee Joint (femur condyle made of Bio
lox®delta) very carefully in 2007. By carefully I mean
that we worked under strict observation criteria as
part of a multicenter study. The patients were informed in detail and the surgeons were selected
and appropriately trained. Our experience with the
ceramic knee here in Rostock and the experiences of
the various centers in Germany, Italy, and Spain that
participated in the study have meanwhile been published [2]. The 5-year results are very convincing. In

* According to the LIMA operation surgical technique, the weight of the
recommended hammer, eventually used, must be less than 500 gr.

CeraNews 1/ 2015

the German center there was one ceramic fracture;
otherwise we observed a very convincing stable fixation and durability of the implants. The recorded
fracture that took place during the study observation was the direct result of a trauma and was treated accordingly [3]. The 10-year results will hopefully
be published in good time.
How important is cement-free knee arthroplasty in your opinion?
Mittelmeier: In the majority of cases, particularly with older patients, we can perform cemented
knee arthroplasty without hesitation. The frequency of cement allergies in the population appears
to be increasing; however, we still do not know
enough about the extent to which the cement allergy actually affects the tissue. The release of ions
and particles (particle surface) is clearly decisive for
the development of the allergy. Since the cement
should not lie in the primary situation of the frictional load of the joint surfaces, the cement allergy
will probably not be as significant as the metal allergy. Nevertheless, cement-free knee replacement
should be able to draw upon stable, safe solutions
as well, also in relation to ceramics. For this reason
we will also need cement-free ceramic solutions
for the knee joint.
Does an ideal treatment cascade already exist in knee arthroplasty? How does it look, in
your opinion?
Mittelmeier: I very much hope that we will have
ceramics available in the various treatment cascades, that is, from unicompartmental knee arthroplasty, to total knee replacement, up to and including posterior stabilized prostheses and all revision
endoprostheses.
How does the future of ceramic knee arthroplasty look to you?
Mittelmeier: There were several failures in the
development of ceramics in hip arthroplasty more
than 40 years ago, which were the fault of the early material development. Ceramic materials have
been significantly improved in the meantime and
offer considerably better conditions for hip and
for knee arthroplasty. I expect that there will have
to be a new, very strong trend to develop ceramic knee arthroplasty with regard to long durability,
the least possible ion release and solutions for revision arthroplasty. Current solutions already being
tested in laboratories are very promising.
Partial resurfacing of the knee or preferably
corrective osteotomy – where are the indication boundaries?
Mittelmeier: A surgical intervention for corrective
osteotomy must also have a sufficiently long-lasting effect. The same is true for partial knee arthroplasty. The two interventions must be carefully

weighed with regard to the patient’s needs and the
condition of the joint. The best possible joint-preserving solution via corrective osteotomy takes priority in making the decision for younger patients.
It is my personal view that the early implantation of
metallic or metal/polyethylene partial components
in the knee joint is not yet a perfected mode of
treatment. Here as well we will be able to choose
ceramic solutions and then have a presumably wider indication. The effects of metal ions and particles on the surrounding, still largely intact cartilage
cannot be considered beneficial.
Robotics at the knee – a necessity or just
marketing?
Mittelmeier: The very adverse results of using robotics on the hip joint in the past have led to a
great deal of mistrust towards the use of robots in
endoprosthetics. The newer types of robots that
are presently being used in abdominal surgery under the optical and tactical control of an experienced surgeon promise a better development. It is
still not clear to what extent these modern robot
types will actually become established on the market in our country, because the profits that can be
made with endoprostheses – a prerequisite for further useful developments – have already reached
the bottom limit. A relatively large amount is being, and must be, saved on implants nationwide
instead of making room for qualitatively better developments. On the other hand, a possible future
form of robot-supported endoprosthetics will have
to undergo very rigorous clinical testing in advance
with respect to applicability, application errors and
error tolerance. In addition, there must then also
be a detailed clinical evaluation of the extent to
which a robot system actually offers advantages
compared with standard treatment by an experienced surgeon.
Knee arthroplasty with preservation of the
anterior cruciate ligament – is that the future?
Mittelmeier: The preservation of the anterior cruciate ligament may be a sensible approach in knee
arthroplasty. To date, however, it has been very
difficult to achieve kinematically satisfactory solutions, as the kinematics of the knee joint is physiologically very individual, and for the anterior cruciate ligament in particular, very high standards are
set regarding the surgical technique and the implant.

Wolfram Mittelmeier, MD, is a professor of
orthopedics and the Director of the Orthopedic
Clinic and Polyclinic at the University Medicine in
Rostock.
Following his doctoral studies and his qualification as a specialist in orthopedics, Mittelmeier
worked first as a consultant and later as a senior consultant at the University Hospital of Lübeck, before moving to the Technical University of M
unich as senior consultant in the Hospital for Orthopedics and Sports Orthopedics. There he established the
biomechanics laboratory and the cell laboratory. In 1999 he received his
postdoctoral lecturing qualification; 4 years later he accepted a chair at
the University of Rostock in the field of orthopedics. Since 2004 he has
served as the director of the orthopedic division of the University Hospital in Rostock.
His main clinical focus is on arthroplasty, revision surgery, children’s orthopedics, and joint-preserving operations. His scientific focus is on biomechanics, implant technology, and worst-case simulations. Since 2005,
he has been a member of the board of the German Society of Orthopedics and Orthopedic Surgery (DGOOC) and of the board of the Association for Orthopedic Research, where he served as president from 2009
until 2013.
Mittelmeier developed the basis of a quality management system for endoprosthesis centers, which became EndoCert; it is audited by committees of the German Society for Orthopedics and Trauma Surgery (DGOU)
and has been implemented nationwide since 2012. Since 2011 he has
been the deputy chairman of the advisory board on orthopedic technology of the German Association of Orthopedic Technology.
In 2014 he served as president of the OTWorld / World Congress of Orthopedic Technology.

revisions will obviously also increase temporarily.
It will be important to establish good procedures
that are as long-lasting as possible with very welltrained operators in order to keep the revision load
as small as possible. ■
References
1. Bergschmidt, Philipp et al., Total knee replacement system with a ceramic
femoral component versus two traditional metallic designs: a prospective
short-term study, J Orthop Surg (Hong Kong). 2013 Dec;21(3):294-9.
2. Bergschmidt, Philipp et al., Prospective multi-centre study on a composite ceramic femoral component in total knee arthroplasty: Five-year
clinical and radiological outcomes, The Knee 2015, DOI: http://dx.doi.
org/10.1016/j.knee.2015.02.003
3. Krueger A P et al., Ceramic Femoral Component Fracture in Total Knee
Arthroplasty:An analysis using fractography, fourier-transform infrared
microscopy, contact radiography and histology, J Arthroplasty 2013, doi:
10.1016/j.arth.2013.11.003)

How do you envision the future of knee replacement?
Mittelmeier: I believe that, as international developments show, knee replacement will have to
be refined. Along with the continually increasing
number of knee replacement worldwide – with the
exception of the German region – the number of
CeraNews 1/ 2015

CASE REPORTS

Primary Knee Arthroplasty in Patients with
Suspected or Confirmed Metal Allergy

Benazzo F, Ghiara M, Rossi SMP
Clinica Ortopedica e Traumatologica, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy

CASE REPORT 1
Primary TKR for advanced arthritis

component (Biolox®delta Multigen Plus, size 3) and
and a poly liner with a height of 12 mm (Fig. 1b).

Diagnosis
A 68-year-old woman with a history of hypertension, coronary artery disease, and multiple allergies
(asthma, dust). The patient had had a painful right
knee due to arthritis for two years. The preoperative X-rays clearly showed severe valgus osteoarthritis with involvement of the lateral compartment
and patellofemoral joint as well as a lateralization
of the mechanical axis
(Fig. 1a).
Indication was for primary TKR with a Multigen
Plus ceramic knee implant (Lima) to avoid crosslinked reaction due to suspected metal allergy.

Therapy
Surgery was performed via a mini mid-vastus approach. Replacement of the knee was done with a
fixed Ti tibial plate (size 2) and a ceramic CR femoral

Postoperative therapy included a femoral nerve
block (naropin) for analgesia and fast rehabilitation
of the knee: The patient began to exercise to regain
range of motion on the first postoperative day, and
she walked with two canes on the second postoperative day. She took non-steroidal anti-inflammatory
drugs (indomethacin) for 3 weeks, as did the other
patients who underwent TKR.
After 4 weeks she was able to do without one cane
and she had very mild pain, which had disappeared
at the 3-month follow-up. The range of motion was
0–115° and the excellent results were confirmed at
the last follow-up. X-rays showed a good restoration
of limb alignment and no radiolucent lines at 6 years
of follow-up
(Fig. 1c). The final clinical KSS was
98 points (excellent), the final functional KSS was
100 points (excellent), and the final OKS was 47.

Figure 1: Primary TKA 68-year old woman: a) lateralization of mechanical axis preoperative, b) postoperative situation, c) follow-up after six years: good limb alignment (© Benazzo)

CeraNews 1/ 2015

CASE REPORT 2
Primary TKR for advanced arthritis
Diagnosis
The patient was a 75-year-old woman with a history
of hypertension, pancreatic neuroendocrine cancer,
diabetes and glaucoma. She had had diffuse pain
in the left knee for 4 years which had been treated
without success with hyaluronic acid injections. The
X-rays showed a primary knee arthritis and a varus
knee. The cartilage degeneration involved all three
compartments
(Fig. 2a), particularly the medial
side and the patellofemoral joint, and the mechanical axis was medialized. She also had a metal allergy
(nickel), so we decided to use a the Multigen Plus
delta ceramic knee.

Therapy
Surgery was performed via a mini mid-vastus approach to the knee. Replacement of the knee was
performed with a fixed Ti tibial plate (size 1) and a
ceramic CR femoral component (Biolox®delta Multigen Plus, size 1) and a poly liner with a height of
12 mm
(Fig. 2b).
Postoperative drug therapy consisted of peridural
analgesia, which allowed fast rehabilitation of the

knee: The patient began to exercise to restore the
range of motion on the first postoperative day, and
she walked with two canes on the second postoperative day. She took, as usual after a TKA, non-steroidal anti-inflammatory drugs (indomethacin) for 3
weeks.
After 4 weeks she was able to do without one
cane and she had no pain. The range of motion was
0–110° and increased to 0–120° at 6 months.
The excellent results were confirmed at the last follow-up at 2 years, and X-rays showed no radiolucent lines, a good patellar height and good patellofemoral tracking
(Fig. 2c). The final clinical
KSS was 99 points (excellent), the final functional
KSS was 100 points (excellent), and the final OKS
was 46. ■

Corresponding Author:
Francesco Benazzo, MD
Director
Clinica Ortopedica e Traumatologica
Fondazione IRCCS Policlinico San Matteo
Viale Camillo Golgi 19
27100 Pavia (Italy)
E-mail: f.benazzo@smatteo.pv.it

Figure 2: Knee of a 75-year old woman: a) preoperative status (lateral/patella), alle three compartments show arthritis damage, b) postoperative
with fixed tibial plate and ceramic femoral component (lateral/frontal), c) two years after surgical intervention (lateral/patella) (© Benazzo)

CeraNews 1/ 2015

SCIENCE

Evidence-based Decision-Making and
Biological Reactions Related to Materials

Usbeck S and Scheuber LF
CeramTec GmbH, Plochingen, Germany

TOPIC 1: EVIDENCE-BASED MEDICINE IN ORTHOPEDICS: WHERE IS THE EVIDENCE?

OCEBM Levels of Evidence download here:
www.cebm.net/ocebmlevels-of-evidence/

Evidence-based medicine continues to grow in importance. Evidence-based medicine came to the fore
in the early 1990s and has been defined as "the integration of best research evidence with clinical expertise and patient values" (Sackett et al. 2000)
[1]. Evidence has always contributed to clinical decision-making. Murray et al. reviewed the evidence
for THA in 1995 [2]. They found that only 30 % of
hip-joint replacements available contained any evidence and emphasized the need for evidence-based
data.
Additional researchers have concluded that the need
for good-quality evidence in the orthopedic literature has remained vital. Unfortunately, the continuous lack of a level of evidence has been established in
many publications. The quality of these publications
is very heterogeneous, making it difficult for clinicians to evaluate the actual evidence level of individual results and recommendations. However, efforts are
being made, e.g. by scientific journals, to bring more
quality and transparency to the subfields of orthopedic surgery and considerably improve knowledge

Guidelines
Systematic reviews /
Metaanalysis
Level
I

ity

Level
III

Val
id

of e
v

ide
nce

Level
II

Level
IV
Level
V

Randomised
controlled trials
Cohort studies
Case-control studies
Case series, case reports
Expert opinion

Figure 1: Evidence of clinical effectiveness: the evidence pyramid (modified from Sackett et al.
2000, [1])

CeraNews 1/ 2015

transfer ("knowledge translation") of science and research into concrete medical practice.
National joint registers have been established to
monitor and improve the outcomes. However, registers differ in methods of data analysis and reporting,
which limits the interpretation of the data. These differences make comparisons among registries difficult
or impossible.

Konan and Haddad, University College Hospitals
London, 2013 summed up the situation in a paper,
saying [3]: "We now routinely rely on registry data
to guide our debates and decisions but we would
be wise to remember that they have inherent weaknesses that limit the interpretation of the data. Compliance issues associated with any data collection
and reporting process limit the quality of the registry data. No robust system is in place to tackle confounding data, and to capture underreported or unreported outcomes. Registries were set up to monitor
survival but the ancillary data that are collected are
not validated. Caution must therefore be exercised
when using registries as high-level evidence. In particular, registry-based results cannot infer causal relationships. Any trend identified should be used as
a trigger for further study rather than as a rigid conclusion."
Evidence-based data should be founded both on results of well-designed studies and on registers that
are able to collect data in large populations and to
identify trends.

s
Bia

Stre
ngt
h

Evidence-based medicine includes a classification system that enables a defined evaluation, based on the
so-called evidence level, of the quality of the studies and particular publications. This system of grading
offers clinicians a simplified rating for clear comparison of performance based on relevant clinical criteria ( Fig. 1).

The Dutch Strategy
Verheyen et al. 2014 and Poolman et al. 2015
[4, 5] reported about the Dutch strategy at a meeting of the European Hip Society 2014 and in a current publication (2015). Problems with large numbers of MoM hip replacements prompted Dutch
orthopedic surgeons to re-evaluate patient safety. The Dutch Orthopedic Association (Nederlandse
Orthopeadische Vereniging, NOV) initiated a taskforce to classify the quality of hip replacements

based on survivorship. New implants or prostheses that do not meet the criteria may be implanted only in the scope of a research program with
approval by the institution's medical ethics review board. NOV offers patients insights into evidence-based quality of the hip implants. The authors are convinced that this will facilitate shared
decision-making by empowering patients with
knowledge about available hip implants.

TOPIC 2: XPE-INDUCED OSTEOLYSIS AND SURFACE DAMAGES
Low wear rates and longer lasting bearing surfaces with biologically inert characteristics are of specific
interest in addressing the needs of patients with a long life expectancy and a high activity level. Highly
cross-linked polyethylene (XPE) has been used in an effort to combat osteolysis and aseptic loosening. Although XPE is more resistant to wear than conventional polyethylene, it remains unknown whether XPE
decreases wear-associated failure of THA and improves longevity at mid-term to long-term follow-up. It
is hypothesized or predicted in publications that the substantial reduction in wear rates observed for XPE
compared with conventional PE may have the biological effect of reducing the rate of periprosthetic osteolysis after THA.
However, at the AAOS 2014, researchers reported about their concerns with XPE in THA in long-term use.
Holubowycz, Howie et al., presented the results of a randomized controlled trial showing that XPE articulations lead to periacetabular osteolytic lesions at 7–10 years after primary THA [6, 7]. Osteolytic lesions
were detected in the absence of clinically significant wear. Moreover, in that study, the incidence was similar in articulations with 28-mm and 36-mm ball head diameter.
A systemic review of randomized controlled trials has now found that wear advantages of XPE did not
translate into less osteolysis and aseptic loosening. XPE-induced osteolysis seems to occur without substantial wear. There is a need to better characterize factors that influence the development of osteolysis
with XPE articulations. There are numerous different XPE materials on the market, produced with various
manufacturing methods which may influence the clinical performance. We also currently know very little
about the bioactivity of these XPE wear particles.

SYSTEMATIC REVIEW OF LEVEL-1 RANDOMIZED CONTROLLED TRIALS
XPE does not decrease osteolysis and wear-related revision rate
Shen et al. 2014 included eight randomized controlled trials (RCT) with mid- to long-term follow-ups comparing XPE with PE in THA [8]. The follow-up periods of the RCT ranged from 5 to 12
years; 735 patients were included in their study.
The studies reviewed were published between
2009 and 2012. This meta-analysis of RCT demonstrated for the first time that the linear wear rate
was lower in the XPE group than in the PE group,
but the incidence of osteolysis and wear-related revision incidence did not differ significantly between
the XPE and PE groups. Although wear of XPE inserts appears to be lower than of conventional PE
inserts, the risk of periacetabular osteolysis around
articulations with XPE has not been eliminated, and
the true incidence remains unknown.

Hence the authors emphasized that XPE has no advantage or clinical benefit over conventional PE in
terms of reducing osteolysis and wear-related revision. This meta-analysis demonstrated that reduced
in vivo XPE wear rates did not improve the clinical
outcome. For this reason, the researchers called for
further long-term RCT on this topic.
The concept of the so-called osteolytic wear threshold remains controversial. Dumbleton et al. 2002
suggested that osteolysis is infrequent with a wear
rate less than 0.1 mm/year and almost absent at a
wear rate less than 0.05 mm/year [9]. Osteolysis is
a complex process and depends on many factors,
including the biological activity of generated wear
particles. Although much is known regarding wear
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properties of cross-linked polyethylenes, there is little information and knowledge regarding the biological activity of the wear particles generated.
Illgen et al. 2008 demonstrated that XPE particles
exhibited an altered bioactivity which was unrelated
to particle size [10]. The scientific issue of whether
and how XPE particles interact with various types
of cells must be investigated further. Some researchers have demonstrated that XPE wear particles are smaller than 1 µm and more inflammatory
than conventional PE particles. In vitro cell culture
studies predicted that submicron wear debris from
XPE might show osteolytic potential comparable to

that of conventional PE over time. It will therefore
be important to understand the bioactivity of XPE
wear particles compared with conventional PE wear
particles, since there is little information and a paucity of available data so far.
To understand the biological response to XPE wear
particles and to determine which material factors,
wear characteristics, and other mechanisms have a
substantial impact on the pro-inflammatory activity of these particles, further studies and research in
this area are needed, as the number of young patients receiving THA continues to grow.

RETRIEVAL STUDY
XPE demonstrated surface damage similar to PE
Pang et al. 2015 compared wear and surface damage in matched retrieved XPE and PE inserts. The
XPE inserts represented all the FDA-approved XPE
inserts of a specific design implanted for at least 1
year [11]. This XPE group was matched to a PE group
of identical design retrieved in the same time period. The authors found no difference between the
groups for total damage score or for the bearing,
rim or backside surface damage scores. Moreover, in
that study, the most common damage modes in the
XPE group were abrasion, scratching, and cold flow.

The most common damage modes in the PE group
were burnishing, abrasion, and cold flow. The mean
abrasion damage score was significantly higher in
the XPE group than in the PE group. With respect to
the lesser amount of volumetric wear measured in
the XPE group compared with the PE group, these
findings were similar to those of other studies.
This paper pointed out the need for further investigations and long-term studies to determine the effects on implant longevity.

References
1. Sackett DL. Straus SE, Richardson WS, Rosenberg W, Haynes RB. Evidence-based medicine: how to practice and teach EBM. 2nd ed., Churchill
Livingstone, Edinburgh 2000

7. Howie DW, Holubowycz OT, Moran CR, Solomon LB. Osteolysis and wear
of large and standard metal on highly cross-linked polyethylene articulations. Annual Meeting ORS 2014: Poster 1773

2. Murray DW, Carr AJ, Bulstrode CJ. Which primary total hip replacement? J
Bone Joint Surg Br 1995;77:520-527

8. Shen C, Tang ZH, Hu JZ, Zou GY, Xiao RC, Yan DX. Does cross-linked polyethylene decrease the revision rate of total hip arthroplasty compared
with conventional polyethylene? A meta-analysis. Orthop Traumatol Surg
Res 2014;100(7):745-750

3. Konan S, Haddad FS. Joint registries. A Ptolemaic model of data interpretation? Bone Joint J 2013;95-B:1585-1586
4. Verheyen CCPM, Schreurs BW, Born PA, Verhaar JAN, Nelissen RGHH,
Goosen J, Poolman RW. Selecting the right hip implant for our patients.
The Dutch strategy. Abstracts from 11th EHS Congress, Stockholm, Sweden, 9-11 October 2014, Hip Int 2014;24(5):526
5. Poolman RW, Verhaar JAN, Schreurs BW, Bom LPA, Nelissen RGHH, Koot
HWJ, Goosen JHM, Verheyen CCPM. Finding the right hip implant for
patient and surgeon: the Dutch strategy – empowering patients. HipInt
2015; DOI: 10.5301/hipint.5000209
6. Holubowycz O, Howie D, Solomon LB, Moran CR. Osteolysis and wear of
large and standard metal on highly cross-linked polyethylene articulations. AAOS 2014: Paper 253

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9. Dumbleton JH, Manley MT, Edidin AA. A literature review of the association between wear rate and osteolysis in total hip arthroplasty. J Arthroplasty 2002;17(5):649-661
10. Illgen RL, Forsythe TM, Pike JW, Laurent MP, Blanchard CR. Highly crosslinked vs conventional polyethylene particles – an in vitro comparison of
biologic activities. J Arthroplasty 2008;23:721-731
11. Pang HN, Naudie DDR, McCalden RW, MacDonald SJ, Teeter MG. Highly
crosslinked polyethylene improves wear but not surfaces damage in retrieved acetabular liners. Clin Orthop Relat Res 2015;473:463-468

TOPIC 3: CORROSION
The issue of taper wear and corrosion at the head-neck junction is not a new phenomenon, but the problems detected with the use of larger metal femoral ball heads in THA have made it more prevalent. Corrosion of metal in medical devices could cause health problems to patients. It has been demonstrated by a
research group led by Hallab and Jacobs 2010 that both soluble metal ions and metal debris produced
during corrosion induce pro-inflammatory responses in human monocytes / macrophages [12]. Corrosion at
the taper junction is still poorly understood as regards relevant clinical pictures and entities. A comprehensive systematic review of the medical publications that determine patient characteristics, implant designs,
symptomatology, clinical pictures and treatment strategies regarding corrosion at this interface is still lacking in the literature. This gap is now being filled by a recent publication from Canadian researchers.

SYSTEMATIC REVIEW AND CASE SERIES
Clinically significant corrosion at the taper junction
Carli et al. 2015 illustrate in a systematic review
and case series that symptomatology following corrosion tends to occur in the intermediate follow-up
period and most often presents within the clinical
picture of aseptic loosening, unexplained thigh pain
or an adverse reaction to metal debris (ARMD) [13].
A total of 24 articles represented 776 cases (754 patients) with documented head-neck corrosion found
at revision surgery. The bearing couples most frequently utilized were MoM (419; 53.9 %) and MoP
(351; 45.4 %), with 13 being cross-linked polyethylene. The head diameters in MoM bearings were
larger (median and mode of 46 mm) than those
used in MoP (median and mode of 36 mm).
12 articles of this review representing 24 cases reported that the trunnion (or male taper) was found intact. In 15 cases this led to revision of only the femoral ball head and the acetabular component, while
the stem remained in situ. Ceramic femoral ball heads
were used with ceramic or polyethylene inserts. Since
the trunnions were used, the recommendation to ensure safe usage of ceramic femoral ball heads would
be to use one with a sleeve (Helwig et al. 2013) [14].
However, Carli et al. remark that sleeves provide
an additional interface for micro-motion and ion exchange to occur. Concerning this aspect it might be
useful to take further data into account.Yet Thorey
et al. 2012 pointed out that they had followed up a
relatively large cohort of patients (91) who had undergone revision from MoP (53), MoM (2), CoC (15),
and CoP (21) bearings to a CoC or CoP bearing with a
sleeve, mostly due to acetabular component loosening
[15]. They did not observe any ceramic ball head fractures or complications related to the sleeve–taper junction such as corrosion / fretting. Jack et al. 2013 used
ceramic ball heads with titanium sleeves in revision
surgeries, placing the sleeves on used trunnions [16].
They did not record any metal ions or radiological evidence of metal wear debris. In a case report by Whitehouse and Duncan 2014, the authors describe the
case of a patient with a painful MoXPE THA [17]. Hip

arthroscopy confirmed the diagnosis of trunnion corrosion. Due to persistent symptoms, the patient was
revised to a CoXPE bearing, utilizing a ceramic femoral
ball head with a sleeve, which was placed on the corroded trunnion. This relieved the patient’s symptoms.
In an in-vitro study, Preuss et al. 2012 also addressed the issue of taper fretting and corrosion for
large ceramic bearings used with an adapter sleeve
(made of Ti-6Al-4V) [18]. The aim of this study was
to investigate the risk of fretting corrosion and wear
and the risk of loosening of the head-taper junction
of such large-diameter CoC bearing devices for revision surgery. The current results from this study confirm that an accurate placement and assembly of
the components as given by the instructions for use
by the manufacturer result in sufficient resistance of
the interfaces against fretting corrosion and wear.
In their retrieval analysis Huot Carlson et al. 2012
also found that metal femoral ball heads were significantly more prone to corrosion of the head taper
(54 %) as compared with titanium-sleeved ceramic ball heads (18 %) [19]. Metal femoral ball heads
were also more associated with corrosion of the
stem compared with ceramic or sleeved ceramic ball
heads. To summarize, there is still a need for further
research and evidence including clinical conditions.

Carli et al. 2015 describe the symptoms among
patients in their own case study group as consisting of groin pain, a palpable mass, recurrent dislocation and adverse local soft-tissue reactions [13].
They also found disproportionately elevated serum
cobalt levels relative to chromium in their case series. They point out that this finding has also been
reported in a large randomized series involving
large-diameter MoM implants. The authors hypothesize that this disproportion could potentially serve
as a diagnostic indicator of an ongoing corrosive
process, and they therefore call for additional studies. Further analysis is also needed to investigate
the overall prevalence of clinical symptomatology.
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Corrosion in large femoral ball heads
Level-I studies support the use of large femoral ball heads in order to decrease the risk of postoperative instability following primary and revision THA. When selecting the appropriate head diameter in hip surgery,
the surgeon must balance the potential risk for dislocation in his patient with the risks inherent in large
femoral ball heads. Corrosion at the modular head-neck taper has been identified as a potential concern.
Symptomatic adverse local tissue reactions can occur secondary to metal debris resulting from corrosion
of the head-neck taper and have been described in the literature.

SYSTEMATIC REVIEW AND CASE SERIES
Ceramic femoral ball heads are more protective against ARMD
Cooper and Della Valle 2014 pointed out in their
paper that ceramic femoral ball heads reduce the
risk of modular taper corrosion at the head-neck
junction [20]. According to the authors, retrieval
studies by various researchers have demonstrated
that the risk of corrosion is not completely eliminated; however, the degree of metal release from taper
junctions is significantly lower compared with met-

al femoral ball heads. Ceramic femoral ball heads,
which are excellent electrical insulators, resulted in
less stem taper corrosion than reported with metal
femoral ball heads. To summarize, it must be emphasized that ceramic femoral ball heads are more
protective against ARMD than metal femoral ball
heads.

TOPIC 4: IMMUNO-ALLERGOLOGICAL INTOLERANCE REACTION TO METAL DEBRIS
RETRIEVAL STUDY

Scratching on MoM bearings as a cause for ARMD
A recent study by Burbano et al. 2014 evaluated
the bearing surface characteristics of MoM implants
revised due to ARMD using different microscopy
techniques [21]. The modular taper junctions were
also evaluated. The aim was to analyze possible failure mechanisms associated with MoM implants and
their correlation to the formation of ARMD.
Severe mechanical scratching was a common characteristic found in all of the MoM retrievals evaluated. The remarkable level of scratching detected indicates that these MoM implants generated a large
amount of metal particle release in vivo. The lack
of evidence of corrosion in the interfaces evaluated suggested that mechanical factors (scratching,
wear) seemed to be a major trigger for ARMD. The
authors pointed out that severe scratching, wear
and metal ion release may have been the principal
cause for adverse peri-implant tissue reactions in
the revised cases. Third-body wear (i.e. bone fragments) could also have played a role.
Amini et al. 2014 pointed out that a better understanding of the diagnosis and treatment of metal
hypersensitivity is essential for orthopedic surgeons
[22]. The authors noted that metal hypersensitivity
is estimated to be responsible for 5 % of TJA failures. The Medline literature database was searched
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to identify articles related to patch testing or LTT for
metal hypersensitivity with TJA. They reviewed 14
TKA and 6 MoM THA case reports involving metal allergy. Half of the patients had a previous metal allergy. One patient had a history of dermatitis or
eczema. The most common presenting symptoms
were pain (55 %), swelling (45 %), and warmth
(20 %). Eczema over the surgery was present in
35 % of cases. 90 % of these symptoms presented
in the first 3 months after implantation. Cobalt and
nickel were found to be the most common metals
causing allergic reactions.
The authors emphasized that metal hypersensitivity
is a diagnosis of exclusion, and that other potential
diagnoses should be carefully excluded. Patch testing and LTT remain the tools of diagnosis both in patients for TJA and in patients with implant failure.
They concluded that options in THA include the use
of CoP and CoC bearing surfaces to minimize the
risk of a hypersensitivity reaction.
The diagnosis, treatment, and clinical outcome of
patients with metal hypersensitivity remains an active area of research.

CASE REPORT
Chromium-induced diffuse dermatitis and lymph-node involvement by
Langerhans cell histiocytosis: CoC THA led to resolution of symptoms
Bizzotto et al. 2014 hypothesized that microparticles of cobalt-chromium and PE may elicit lymphadenopathy with histiocytosis, but a combined diffuse dermatitis and lymph-node involvement by
Langerhans cell histiocytosis induced by chromium
after MoM hip resurfacing have not been previously
described [23].
General clinical signs such as skin redness, prolonged
generalized pruritus, and psoriatic-like dermatitis with desquamation may be related to delayed
type-IV hypersensitivity reaction. The authors reported that lymphadenopathy with diagnosis of special Langerhans cell histiocytosis may be due to prolonged activation of the type-IV immune response.
In their reported case, a 60-year-old male patient
presented with a 3-year history of diffuse dermatitis
5 years after implantation of MoM hip resurfacing.
The symptomatic patient had a prolonged pruritus
unresponsive to antihistamines and corticosteroids.
Dermatological treatments were not successful. The
patient had no past history of atopy or metal-contact dermatitis. Diffuse lymphadenopathy on both
sides of the inguinal region was detected. A skin

biopsy showed nonspecific perivascular lymphocytic
infiltrate in the upper dermis associated with histiocytes. A patch test revealed chromium-sulfate hypersensitivity. Higher chromium and cobalt levels
in serum were measured. The biopsy of an inguinal lymph node demonstrated large aggregates of
Langerhans cells, suggesting delayed type-IV hypersensitivity.
The authors pointed out that only replacement of
the hip implant using non-MoM surfaces may definitely resolve such clinical symptoms. Metallosis was
observed intraoperatively. The stable MoM hip implant was replaced by a cementless THA using a
CoC bearing (Biolox®delta). The dermatitis resolved
3 months after revision surgery. The lymph nodes
decreased in volume. The serum chromium level
normalized, and the patient was completely free of
any symptoms 1 year after revision surgery.
The authors are concerned that chromium and cobalt toxicity may be under-recognized and that physicians who are not familiar with this issue may
therefore misdiagnose systemic symptoms and lack
adequate treatment.

CASE REPORT AND ANIMAL STUDY

Chronic allergic contact dermatitis caused by an orthopedic metal implant promotes
skin cancer
Long-term consequences of chronic contact dermatitis caused by an orthopedic metal implant are still
poorly understood. This remains an active area of
research.
Dehmeri et al. 2014 presented a rare clinical case
of an invasive squamous cell carcinoma (SCC) that
developed in the context of nickel allergy from a
subcutaneous metal implant [24]. The 46-year-old
woman had no history of skin cancer. An ankle fracture was repaired with open reduction and internal
fixation with placement of a metal rod on the lateral
aspect of her fibula for stabilization. The patient developed a non-healing skin lesion on her left ankle
overlying the metal implant and surgical wound site.
She was allergic to nickel in the metal implant. The
implant was removed 1 year after surgery, but the
skin lesion persisted. The patient presented to the
hospital with a 3-year history of the ulcerated skin
lesion. A biopsy demonstrated a well-differentiated,
invasive SCC consistent with a Marjolin ulcer. The
SSC was surgically excised and did not recur during
a 2-year follow-up period.

The authors concluded that the development of
a SCC in a patient without history of skin cancer
strongly suggested the chronic allergic contact dermatitis surrounding the surgical wound culminated
in cancer formation. They initiated an animal study
(mice) to examine the tumor-promoting potential of
contact dermatitis. Findings confirmed that chronic exposure to a hapten-producing allergen induces
tumor-promoting inflammation in the skin.

Furthermore, the researchers examined the immune environment of the SCC that developed in
the patient and found that the patient’s inflammation was the driver of the carcinogenesis and not
secondary or reactive to cancer development itself.
The authors therefore concluded that these findings provide clear evidence for the tumor-promoting property of chronic allergic contact dermatitis.
A chronic allergic contact dermatitis caused by constant exposure to an allergen can lead to the development of an aggressive and invasive SCC in areas where a significant burden of preexisting cancer-initiated cells is present (i. e., sun-exposed skin).
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SCIENCE

It is interesting to note that contact allergy to metal
dental restorations is discussed in scientific publications as a potential risk factor for development of
intraoral squamous cell carcinoma (Hougeir et al.
2006, Weber et al. 2012) [25, 26].
Moreover, this rare clinical case highlights the importance of patch testing prior to the implantation
of medical devices especially in patients with a reported history of metal allergy. The authors suggested a close monitoring of patients with such implants placed in close proximity to the skin to avoid
a chronic allergic dermatitis and the possibility of
developing SCC. ■

Corresponding Authors:
Sylvia Usbeck (Clinical Affairs Manager)
Leslie F. Scheuber (Senior Product Specialist Recon)
CeramTec GmbH Medical Products Division
CeramTec-Platz 1–9
D-73207 Plochingen (Germany)
E-mail: s.usbeck@ceramtec.de
E-mail: l.scheuber@ceramtec.de
www.biolox.com

References
12. Caicedo MS, Pennekamp PH, McAllister K, Jacobs JJ, Hallab NJ. Soluble
ions more than particulate cobalt-alloy implant debris induce monocyte
costimulatory molecule expression and release of proinflammatory cytokines critical to metal-induced lymphocyte reactivity. J Biomed Mater Res
2010;93A:1312-1321
13. Carli A, Politis A, Zukor D, Huk O, Antoniou J. Clinically significant corrosion at the head-neck taper interface in total hip arthroplasty: a systematic review and case series. Hip Int 2015;25:7-14
14. Helwig P, Konstantinidis L, Hirschmuller A, Bernstein A, Hauschild O, Sudkamp NP, Ochs BG. Modular sleeves with ceramic heads in isolated acetabular cup revision in younger patients-laboratory and experimental
analysis of suitability and clinical outcomes. Int Orthop 2013;37:15-19
15: Thorey F, Thiengwittayaporn S , Thiengwittayaporn S , Windhagen H. Early results of revision hip arthroplasty using a ceramic revision ball head.
Semin Arthroplasty 2011;22:284-289
16. Jack CM, Molloy DO, Walter WL, Zicat BA, Walter WK The use of ceramic-on-ceramic bearings in isolated revision of the acetabular component.
Bone Joint J 2013;95-B:333-338
17. Whitehouse MR, Duncan CP. Arthroscopy as a diagnostic tool for painful
trunnion corrosion after hip arthroplasty. Knee Surg Sports Traumatol Arthrosc 2014;Jul 22 [Epub ahead of print]
18. Preuss R, Haeussler KL, Flohr M, Streicher RM. Fretting corrosion and
trunnion wear – is it also a problem for sleeved ceramic heads? Semin Arthroplasty 2012:23:251-257
19. Huot Carlson JC, Van Citters DW, Currier JH, Bryant AM, Mayor MB, Collier JP. Femoral stem fracture and in vivo corrosion of retrieved modular
femoral hips. J Arthroplasty 2012;27:1389-1396
20. Cooper HJ, Della Valle CJ. Large diameter femoral heads. Is bigger always
better? Bone Joint J 2014;96-B(11 Suppl A):23-26
21. Burbano M, Russell R, Huo M, Welch R, Roy D, Rodrigues DC. Surface
characterization of retrieved metal-on-metal total hip implants from patients with adverse reaction to metal debris. Materials 2014;7:1866-1879
22. Amini MH, Mayes WH, Tzeng A, Tzeng TH, Saleh KJ, Mihalko WM. Evaluation and management of metal hypersensitivity in total joint arthroplasty:
a systemic review. J Long-Term Eff Med Implants 2014;24:25-36
23. Bizzotto N, Sandri A, Trivellin G, Magnan B, Micheloni GM, Zamò A,
Bernardi P, Sbarbati A, Regis D. Chromium-induced diffuse dermatitis and lymph node involvement by Langerhans cell histiocytosis after
metal-on-metal hip resurfacing. Br J Dermatol 2014;10, doi: 10.1111/
bjd.13517 [Epub ahead of print]

CeraNews 1/ 2015

24. Demehri S, Cunningham TJ, Hurst EA, Schaffer A, Sheinbein DM, Yokoyama WM. Chronic allergic contact dermatitis promotes skin cancer. J Clin
Invest 2014;124:5037-5041
25. Hougeir FG, Yiannias JA, Hinni ML, Hentz JG, El-Azhary RA. Oral metal
contact allergy:a pilot study on the cause of oral squamous cell carcinoma. Int J Dermatol 2006;45:265-271
26. Weber ME, Yiannias JA, Hougeir FG, Kyle A, Noble BN, Landry AM, Hinni
ML. Intraoral metal contact allergy as a possible risk factor for oral squamous cell carcinoma. Ann Otol Rhinol Laryngol 2012;121:389-394

Further Reading
Callary SA, Holubowycz O, Howie D. Wear of large metal on highly cross.
linked polyethylene articulations measured by RSA. AAOS 2014: Paper
250
Endo M, Tipper JL, Barton DC, Stone MH, Ingham E, Fisher J. Comparison of wear, wear debris and functional biological activity of moderately
crosslinked and non-crosslinked polyethylenes in hip prostheses. Proc Inst
Mech Eng H 2002;216:111-122
Fisher J, McEwen HM, Tipper JL, Galvin AL, Ingram J, Kamali A, Stone
MH, Ingham E. Wear, debris, and biologic activity of cross-linked polyethylene in the knee: benefits and potential concerns. Clin Orthop Relat Res
2004;428:114-119
Griffin XL, Haddad FS. Evidence-based decision making at the core of orthopaedic practice. Bone Joint J 2014;96-B:1000-1001
Ingram JH, Stone M, Fisher J, Ingham E. The influence of molecular
weight, crosslinking and counterface roughness on TNF-alpha production
by macrophages in response to ultra high molecular weight polyethylene
particles. Biomaterials 2004;25:3511-3522
McCulloch P, Altman DG, Campbell WB, Flum DR, Glasziou P, Marshall JC,
et al. No surgical innovation without evaluation: the IDEAL recommendations. Lancet 2009;374:1105-12
Padman M, Ingram JH, Shaw DL, Fisher J, Ingham E. Biological reaction
to conventional and cross-linked UHMWPE’s in vivo. Annual Meeting ORS
2005: Poster 1688

Mid-term Results of Modern Ceramic-on-Ceramic
Total Hip Arthroplasty
Laforgia R1, Pelone F2, Porporati AA3, Santovito L1, Piconi C4
Mater Dei Hospital, Bari, Italy; 2Kingston University and St. George’s, University of London, London, Great
Britain; 3CeramTec GmbH, Plochingen, Germany; 4Catholic University, Orthopedics and Traumatology Institute, Rome, Italy

The use of CoC bearings in total hip arthroplasty is growing worldwide. Especially bearings larger than 32 mm have been confirmed as a valid option for increased range of motion (RoM) and
stability combined with extremely low wear, and some authors are suggesting that this coupling
is the gold standard in hip arthroplasty. To characterize the outcomes of modern CoC bearings,
a retrospective study was performed on patients who underwent hip arthroplasty with alumina
composite in 3 clinical centers located in the Puglia region of Italy.

Materials and Methods

Results

142 patients who underwent hip arthroplasty with
CoC bearings (Biolox®delta, CeramTec, Germany)
were enrolled in this study, carried out at 3 clinical
centers located in Puglia, Italy. Mean follow-up time
was 47.6 months (SD: 7.9; minimum 11.7, maximum: 68.4). Mean patients’ age was 68 (SD: 11;
minimum: 38, maximum: 86). 63 patients (44.4 %)
were male, and the mean BMI was 27.6 (SD: 4.2;
minimum: 18.8, maximum: 45.0).

The main clinical outcomes are described in
Table 1. No cases of osteolysis and socket instability were observed. One patient suffered from

74 bearings had a diameter of 36 mm (52.1%), and
55 bearings a diameter of 32 mm (38.7 %), while
bearings of 40 mm and 28 mm in diameter were implanted in eight (5.6 %) and five (3.5 %) cases, respectively.
A descriptive analysis of the sample was carried
out in terms of mean, standard deviation (SD), and
range for continuous variables and absolute and
relative frequencies for qualitative ones. An assessment of the difference in distribution of the main
demographic and clinical characteristics of the patients was performed. The Wilcoxon-Mann-Whitney
and Kruskal-Wallis tests were used to evaluate differences between groups for quantitative variables.
The chi-square test was used to compare data from
qualitative variables.
The association between quality of life (in terms of
HOOS and SF-12 scores) and bearing characteristics
was tested with linear regression models. Gender,
BMI, and all variables associated with the analyzed
outcomes with a p-value lower than 0.25 were introduced in the linear regression models. Analysis
was performed with the SPSS 13.0 for Windows
software. Statistical significance was set at p=0.05.

T he abstract is based on
results of a clinical trial
(Level of Evidence III)

Socket inclination, degrees [mean (SD)]

45.4 (4.4)

Osteolysis [n (%)]

0 (0)

Socket instability [n (%)]

0 (0)

Stem position [n (%)]

Neutral

127 (89.4)

Non-neutral

15 (10.6)

Valgus

3 (2.10)

Varus

12 (8.5)

Stem instability [n (%)]

1 (0.7)

Leg length discrepancy [n (%)]

25 (17.6)

Leg length discrepancy, mm [mean (SD)]

11 (9)

HOOS P [mean (SD)]

92.4 (10.5)

HOOS S [mean (SD)]

91.5 (11.3)

HOOS A [mean (SD)]

91.2 (11.8)

HOOS Sp [mean (SD)]

84.5 (18.5)

HOOS Q [mean (SD)]

84.6 (18.0)

SF12 [mean (SD)]

31.0 (2.7)

Reported noises
(all not reproducible at control)

Squeaking [n (%)]

3 (2.1)

Clicking [n (%)]

3 (2.1)

Snapping [n (%)]

0 (0)

Popping [n (%)]

0 (0)

Grinding [n (%)]

1 (0.7)

Table 1: Main clinical outcomes of the DESIT (DElta Study ITaly) patients (n=142)

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>28°

100
90
Patients´ satisfaction index (%)

80
70
60
50
40
30
20
10
0

HOOS P

HOOS S

HOOS A

HOOS Sp

HOOS Q

SF 12

HOOS: Hip dysfunction and Osteoarthritis Outcome Score; P = pain; S = symptoms; A = activity limitations in daily living; Sp = function in sport and recreation;
Q = quality of life

Figure 1: Patients’ satisfaction index versus bearing diameter

stem instability (0.7 % of all patients). 15 stems
(10.6 %) were in a non-neutral position. 25 patients (17.6 %) showed leg length discrepancy, with
the average difference in length being 11 mm (SD:
9 mm). Although 3 patients reported squeaking
(2.1 %), a further 3 reported clicking, and one other
patient (0.7 %) grinding, none of these noises could
be replicated at control. No patients reported either
snapping or popping.
Variables tested for association with quality of life in
terms of HOOS and SF-12 at the univariate analysis
were patient type, follow-up time, socket inclination, stem position (neutral vs. non-neutral – varus
and valgus), and leg length difference (in mm). Os-

teolysis, socket instability and stem instability were
excluded from the analysis because of low or null
variability among the patients.
Higher BMI values were associated with better
quality of life according to the SF-12 scale, while
leg length discrepancy was associated with a worse
outcome. Age was the only variable associated
with health quality outcomes in terms of HOOS
and SF-12 in the multivariate analysis. Specifically, on multivariate analysis older age was associated with worse health quality outcomes in terms of
both SF-12 and four of the five patient-relevant dimensions of the HOOS questionnaire – i. e., pain
(HOOS P), symptoms (HOOS S), activity limitations

Renato Laforgia, MD, is the director of the Orthopedics and Neuro-Rehabilitation Unit of the Mater Dei Hospital in Bari, Italy (CBH Group).
He is a representative of the Puglia Region in the National Committee of
the Italian Health Authority (Istituto Superiore di Sanità) for the start-up of
the Italian Orthopedic Prostheses Registry.
F ormerly, Laforgia was the director of the Orthopedics and Traumatology
Service in the Matera City Hospital (Italy), after having served as an orthopedic surgeon in Busto Arsizio (Italy), Bari, Wrightington (UK), and Maputo
(Mozambique). He has served as the president of the Apulo-Lucanian Orthopedic Society (APLOTO).
During his 30-year career, Laforgia has performed more than 30,000 operations, including more
than 2,000 hip replacements and more than 1,500 knee replacements.
He has taught orthopedics and traumatology at the Universities of Bari and L’Aquila (Italy) and at the
University of Maputo (Mozambique).
His main research interests are the biomechanics of healthy and pathological hips, the technique of
hip surgery, and the development of new osteosynthesis instrumentation. He is a member of the
Standardized Audit of Hip Fractures in Europe (SAHFE) Group for the study of the economic impact
of femoral neck fractures, and a member of the Italian Health Ministry´s working group that assesses the feasibility of a neck-fractures registry in Italy.

CeraNews 1/ 2015

in daily living (HOOS A), and function in sport and
recreation (HOOS Sp). None of the analyzed variables was associated with the HOOS Q outcome at
the multivariate analysis.
No statistically significant differences were observed between unilateral and bilateral interventions in terms of SF-12 and between pain, other
symptoms, function in daily living and function in
sport and recreation according to the HOOS score.
However, statistically significant differences were
observed between the unilateral (mean score:
85.2) and bilateral intervention (mean score: 78.8)
in terms of quality of life according to the HOOS
Q score. Patients with THR bearings larger than
28 mm in diameter showed higher HOOS and SF12 scores. The differences were statistically significant ( Fig. 1).

Figure 2: CoC bearings for hip a rthroplasty

placements, while absence of osteolysis and of ceramic fractures confirms the excellent mechanical
and wear behavior of CoC bearings ( Fig. 2). ■

Conclusions
In summary, the only bearing-related complications
reported by the patients included in the DESIT study
at about 4 years' mean follow-up are transient noises. Bearing diameter larger than 28 mm was shown
to improve patients’ satisfaction with their hip re-

Corresponding Author:
Renato Laforgia, MD
Director Orthopedics and Neuro Rehabilitation Unit
Mater Dei Hospital (CBH Group)
10, Via Samuel F Hahnemann
70126 Bari (Italy)

CeraNews 1/ 2015

SCIENCE

2015 Update on an Evolving Perspective for
Taper Corrosion in Total Hip Arthroplasty

Kurtz SM
Implant Research Center School of Biomedical Engineering, Science, and Health Systems,
Drexel University, Philadelphia, USA

Taper corrosion is an old issue for today’s modern implants. In recent years, however, taper
corrosion has re-emerged as a clinical concern, first with certain large-head metal-on-metal hip
designs, then also with modular femoral necks, and even in selected cases with modern metalon-polyethylene bearing couples. Our group was among the first to identify ceramic femoral
ball heads as a potential solution to taper corrosion [1]. In the past few years we have pursued
research to better understand and quantify the amount of metal that is released from contemporary ceramic and CoCr femoral ball heads. The purpose of this article is to briefly summarize
some of our latest findings, presented at the ASTM Symposium on Taper Corrosion 2014 [2] and
in posters at the 2015 Meeting of the Orthopedic Research Society [3, 4]. We want to continue
to share an evolving perspective on this topic based on our group’s recent research.

Our group began to study the hip implant retrieval
collection at the Implant Research Center at Drexel University to compare taper corrosion in ceramic head systems with that in metal head systems
[1]. We have spent a few years studying carefully
matched implants in the two 50-implant cohorts
(100 patients total) to account for all the variables
influencing taper corrosion and to focus on the
difference between ceramic-metal and metal-metal tapers. First of all, we excluded from the study
any hip implant systems with modularity besides
the head-neck interface. This means that there
were no ceramic heads with metal sleeves in the
study, nor were there modular necks or modular stems. The ceramic heads were all Biolox®,
Biolox®forte or Biolox®delta heads produced by
CeramTec. We observed significantly less corrosion among the stems in the ceramic head cohort
as compared with the metal head cohort, and we
published these data in 2013 [1].

Reduced metal release with ceramic
What we didn’t know at the time was to what degree ceramic heads reduced metal release, and
whether metal release was mitigated at the head
taper, stem taper, or both. We spent over a year developing and validating a highly sensitive technique
to measure the microscopic volumes of metal that
are released in CoCr femoral ball heads and metal stem tapers [4]. After re-examining our previous
matched 50–50 cohort of ceramic and femoral ball
heads, we found that the ceramic cohort exhibited
over 90 % less metal release, in terms of volumetric material loss, when compared with the CoCr cohort. When focusing on the CoCr head cohort, we
found that the vast majority of the metal release –
again, over 90 % – was liberated from the femoral
ball head rather than from the stem taper. These
CoCr heads were all on MoP bearings.

Mechanical integrity influences corrosion
Interested in Retrieval Research? How You Can Help.
As our retrieval research continues, access to explanted ceramic heads
and stem pairs with over ten years in vivo, as well as to ceramic heads
incorporating metallic sleeves (e. g., Delta option heads), would be extremely useful. If you are interested in collaborating with our multi-institutional retrieval research program by providing explanted devices and
associated (de-identified) clinical data, please do not hesitate to contact
the author (skurtz@drexel.edu). We have established protocols for the
shipping of retrieved implants internationally, and we currently collaborate with over 15 clinical centers in the USA and Europe.

CeraNews 1/ 2015

Retrieval research on taper corrosion continues to
be challenging because of the many relevant and
potentially confounding factors: The implantation
time and flexural rigidity of the stem are two such
factors. We were curious to see if the mechanical integrity of the taper connection would influence the
corrosion at the head-neck interface [3]. In the laboratory, previous researchers had shown that impaction force can affect the amount of micromotion,
fretting, and corrosion under in vitro conditions [5].
We asked if such a situation might also be applicable in vivo. To answer this question, we studied 46

retrieved hip systems that did not have the headstem taper intraoperatively disassembled. These devices had been revised for infection, loosening, and
periprosthetic fracture. We found that for devices
implanted for between 5 and 10 years, there was
an inverse correlation between the corrosion damage of the taper and the strength of the taper junction, recorded as the force required to disassemble
the head from the stem taper. In other words, the
weaker the interlock between head and the taper,
the more corrosion was observed at the retrieved
modular taper junction. Keep in mind that this is a
pilot study, but these preliminary data do lend further support to the plethora of factors – some wellknown for years, others only being discovered today
– that influence clinical manifestations of corrosion
at the head-neck interface.

Trunnion surface morphology
not relevant
One design factor, namely stem surface roughness,
has recently been suggested to influence taper corrosion based on in vitro experiments [6]. For this reason, we also decided to study the effect of this variable on taper corrosion in explanted hip components
with CoCr femoral ball heads [2]. We asked whether
components with "microgrooved" stem tapers have
higher fretting-corrosion damage scores than components with "smooth" stem tapers. In order to answer this question, we performed a retrieval analysis of 398 paired femoral ball head and stem THA
components. Using multivariate analysis of covariance, we found that implantation time (p<0.0001),
apparent engagement length (p<0.0001), flexural rigidity (p=0.008), and head size (p=0.04) were significant factors in fretting-corrosion head-damage
scores. Following adjustment for these factors, surface topography (p=0.97) was not associated with
fretting-corrosion damage. Overall, the results of
this study do not support trunnion surface morphology as a contributing factor to fretting and corrosion
damage at the modular CoCr head-neck interface.

Acknowledgements: The author would like to thank Sevi Kocagoz,
Christina Arnholt, Genymphas Higgs, and Dan MacDonald, Drexel University, and Richard Underwood, Ph.D., Exponent, for their contributions to
the corrosion research summarized in this article, as well as for their insights and many helpful discussions.

References
1. Kurtz SM, Kocagoz SB, Hanzlik JA, Underwood RJ, Gilbert JL, Macdonald
DW, Lee GC, Mont MA, Kraay MJ, Klein GR, Parvizi J, Rimnac CM, Do ceramic femoral heads reduce taper fretting corrosion in hip arthroplasty? A
retrieval study. Clin Orthop Relat Res 2013;471:3270–3282
2. Arnholt C, Underwood RJ, MacDonald DW, Higgs G, Chen AF, Klein G,
Hamlin B, Lee GC, Mont M, Cates H, Malkani A, Kraay M, Rimnac CM,
Kurtz SM, Does micro-grooved surface topography influence fretting corrosion of tapers in THA? Classification and analysis of surface topography.
ASTM Symposium on Taper Corrosion in Total Hip Replacement Devices
2014, New Orleans, USA
3. Higgs GB, Siskey RL, Gilbert JL, Mihalko WM, Rimnac CM, Kurtz SM, What
effect does the strength of the taper connection have on taper damage
in retrieved total hip devices? Trans Orthop Res Soc 2015; Poster Session
PS2-154:1741
4. Kocagoz SB, Underwood RJ, MacDonald D, Gilbert JL, Rimnac CM, Kurtz
SM Metal release in ceramic and CoCr heads at the modular junction: a
matched cohort retrieval study. Trans Orthop Res Soc 2015;Poster Session
PS1-065:0887
5. Mroczkowski ML, Hertzler JS, Humphrey SM, Johnson T, Blanchard CR, Effect of impact assembly on the fretting corrosion of modular hip tapers. J
Orthop Res 2006; 24:271–279
6. Panagiotidou A, Meswania J, Hua J, Muirhead-Allwood S, Hart A, Blunn G,
Enhanced wear and corrosion in modular tapers in total hip replacement
is associated with the contact area and surface topography. J Orthop Res
2013;31:2032–2039

Corresponding Author:
Steve M. Kurtz PhD
Implant Research Center School of Biomedical
Engineering, Science, and Health Systems,
Drexel University
3401 Market Street, Suite 300
Philadelphia, PA 19104 (USA)
E-mail: skurtz@drexel.edu

Our group’s ongoing retrieval research continues
to uncover important implications for metal debris
generation in modular hip systems. It is now clear
that ceramic heads eliminate the potential for metal release from the CoCr head and reduce tribo
corrosion of metal stem tapers to a level that is exceedingly challenging to measure today. Our pilot
research with retrieved CoCr heads suggests that
mechanical integrity of the taper could play an important role in its susceptibility to taper corrosion
in vivo. Furthermore, our retrieval data do not support stem taper morphology (i. e., smooth vs. microgrooved stem tapers) as a significant factor to explain fretting and corrosion taper damage in vivo.
Expect future updates on the status of taper corrosion research at conferences in the coming year. ■
CeraNews 1/ 2015

SCIENCE REPORT

Fretting and Corrosion
Discussion of Methods for Assessment and Testing
Report on the Symposium on Modularity and Tapers in Total Joint Replacement
Devices, November 10, 2014, New Orleans, USA

Pandorf T
CeramTec GmbH, Plochingen, Germany

In recent years, fretting and corrosion of modular connections in hip endoprosthetics have been
more and more under discussion, leading to an increased number of publications related to the
topic. Also modular connections with ceramic ball heads on stem tapers or ceramic ball heads
with sleeves on stem tapers for revision surgeries have been investigated in this framework.
Nevertheless, the experts are still not in agreement on the means and methods for qualitative
and quantitative assessment of the corrosion events occurring at the taper connections. Moreover, the in-vitro reproduction of the clinically observed corrosion phenomena is a topic of ongoing research. To address these issues, the American Society for Testing and Materials (ASTM)
and the American Academy of Orthopedic Surgeons (AAOS) organized a symposium held in
New Orleans on November 10, 2014, with notable experts on the podium.

The main purpose of the symposium was to provide
a forum for scientific exchange and an opportunity to find consensus on common methods for the
assessment and testing of fretting and corrosion,
possibly leading to the development of appropriate
international standards. Many aspects were taken
into account, with special emphasis on the following subjects:
• Characterization of fretting, corrosion and the
resulting adverse tissue reactions,
• significance of explants,
• current and prospective test procedures, and
• design parameter for taper connections in joint
endoprostheses.
Approximately 200 participants from science, from
industry, from the Food and Drug Administration
(FDA), and from several legal organizations followed the 27 presentations which were divided
into five different sections according to their main
focus. At the end of each section, the participants
had the opportunity to intensively discuss the contents of the presentations with the presenters. Furthermore, altogether 15 research groups took the
opportunity to present their newest results within
a poster session. Organizers and chairmen of the
symposium were A. Seth Greenwald (Cleveland),
Steven Kurtz (Philadelphia), Jack Lemons (Birmingham), and William Mihalko (Memphis).

Adhesion of inflammatory cells could
cause corrosion
In his presentation, Lemons showed the difficulty of
distinguishing between the different possible corroCeraNews 1/ 2015

sion mechanisms, such as galvanic corrosion, fretting corrosion, crevice corrosion, and pitting corrosion, and of simulating these mechanisms in vitro.
Jeremy Gilbert (Syracuse) reported that inflammatory and immune cells attach to CoCrMo surfaces
in vivo and start or amplify corrosion processes. Microscopical investigations of explanted hip components (MoM, MoP) and knee implants supplied for
the first time evidence for this type of corrosion.
These corrosion processes have been observed independent of the metal alloy, implant design, and
type of polyethylene. It is largely unknown which
stimuli trigger the cell activity.
With the help of 843 examined retrievals, Kurtz illustrated in his presentation that the loss of volume
due to corrosion processes is much larger on the
metal ball head tapers than on the stem tapers. Furthermore, using 398 explanted stems from MoPbearings, he provided evidence that the surface topography of the stem tapers does not influence the
qualitative and quantitative degree of corrosion on
either on the metal ball head tapers or the stem tapers.

Legal aspects: large product range,
demand on improved test methods
Carlos Lavernia (Miami) complained about the
large number of different taper designs which may
exist within the product range of a single prosthesis
company, harboring the risk of mix-and-match. He
used the term "lawyeritis", which may prevent further proper scientific investigation of the topic.

John Goode from the FDA noted that improved
test methods are urgently necessary because all
the implants exhibiting clinically relevant problems
have successfully passed the standardized testing
prior to market release. Two representatives of a
US law office stated that appropriate standards
and guidelines might significantly ease possible litigations. The currently common active recruitment
of patients for litigations increasingly falsifies the
available data and affects the scientific root cause
analysis.
Several important conclusions have been drawn on
the basis of contemporary knowledge: in the test
procedures, more and more attention is given to the
selection of those test parameters having the greatest influence on the simulation of clinically relevant
failure modes, e. g., the test fluid or the loading scenario. In order to assess these clinically relevant failure modes with the help of retrievals, it is necessary
to establish uniform cleaning procedures for the tapers. Only then it is possible to assess the retrievals
on the basis of qualitative scores and quantitative
measurements.

ination: So far, only a few revision surgeries have
been performed due to symptoms which are related exclusively to fretting and corrosion, whereas a
large number of retrievals show clear signs of these
phenomena. A necessity to develop different stem
taper designs for ceramic and metal ball heads –
with respect to either the shape or the surface – is
not seen by the experts at this time. ■

References
1. Lemons JE. Experience & Opinions on Modular Connections for Surgical
Implant Devices. ASTM International Symposium on Modularity and Tapers
in Total Joint Replacement Devices, New Orleans 2014, Abstract (talk 1)
2. Kurtz SM et al. Is Taper Fretting Corrosion a Threat to the Clinical Performance of Large-Diameter Highly Crosslinked Polyethylene Bearings?
ASTM International Symposium on Modularity and Tapers in Total Joint
Replacement Devices, New Orleans 2014, Abstract (talk 9)
3. Higgs GB et al. Characterizing the Strength of the Taper Connection & its
Effect on Taper Damage in Retrieved Total Hip Devices. ASTM International Symposium on Modularity and Tapers in Total Joint Replacement Devices, New Orleans 2014, Abstract (talk 10)

4. Gilbert JL. State-of-the-Art Understanding of In Vivo Modular Taper Corrosion & In Vitro Testing. ASTM International Symposium on Modularity
and Tapers in Total Joint Replacement Devices, New Orleans 2014, Abstract (talk 18)

Impact of fretting and corrosion
on clinical results

5. Laverna CJ et al.The Role of Design Parameters and Microstructure in
the Corrosion and Fretting of Hip Taper Interfaces: A Retrieval Study.
ASTM International Symposium on Modularity and Tapers in Total Joint
Replacement Devices, New Orleans 2014, Poster

The scientific and technological meeting showed
that remarkable progress has been made in assessing and testing fretting and corrosion since the last
meeting of this kind in November 2013. It also revealed that the complex relationships and the large
number of influencing factors leading to the clinically observed failure modes can be simulated only
roughly in vitro. There was agreement that the importance of fretting and corrosion related to clinical problems for patients requires further exam-

Corresponding Author:
Thomas Pandorf PhD
(Senior Manager Applied Science)
CeramTec GmbH
CeramTec Platz 1 – 9
73207 Plochingen (Germany)
E-mail: t.pandorf@ceramtec.de

CeraNews 1/ 2015

SCIENCE

Does Bearing Influence Septic Loosening of
primary Total Hip Arthroplasty?

Bordini B, Caputo D, Stea S
RIPO Register c/o Medical Technology Laboratory, Istituto Ortopedico Rizzoli, Bologna, Italy

A cohort of 36,396 implants of primary total hip arthroplasties was considered, extracted from
the italian Register of Prosthetic Orthopedic Implants (RIPO). Of these, 49 % have CoC articular coupling, 23.4 % CoP, 19.5 % MoP, and 8 % MoM. Survival analysis was performed, the end
point being revision due to sepsis. It was shown that age at surgery and body mass index do
not influence septic loosening, while articular coupling and male gender do. In detail, CoC
coupling reduces the risk of septic failure compared with MoM. Men have a higher risk than
women.

T he abstract is based on
results of a clinical trial
(Level of Evidence III)

Beginning on January 1, 2000 a Register for Orthopedic Prosthetic Implants (RIPO) was established in the Italian region of Emilia Romagna. The
register collects data on all primary hip replacements and revision surgery performed in public
and private hospitals of the region [1]. Surgeons
provide data on specific register forms, which are
completed before patients are discharged. The
Coupling

Number of
implants (n)

Age, mean
(years)
and range

Prop.
of obese
(%)

Prop.
of female
(%)

Revisions
for septic
loosening (n)

CoC

17,858

65.7 (13–93)

MoP

7,104

71.1 (20–95)

CoP

8,524

70.3 (22–92)

MoM

2,910

61.4 (16–87)

The aim of the analysis was to determine whether
there is an influence of articular coupling on septic
loosening.

Methods

Table 1: Cohort of 36,396 uncemented primary implants analyzed statistically

Hazard ratio

95% lower
bound

95% upper
bound

p-value

Gender
(reference male)

0.6

0.3

0.9

0.03

BMI class
(reference obes)

0.9

0.7

1.3

0.97

Bearing
(reference CoC)

0.98

0.95

1.0

0.09

MoM

3.1

1.6

6.2

0.003

MoP

1.2

0.6

2.3

0.66

CoP

1.2

0.6

2.3

0.66

Table 2: Results from Cox model: A hazard ratio (HR) >1 indicates risk increase, a HR <1 risk
reduction (significant data are in boldface)

CeraNews 1/ 2015

register capture rate is nearly 98 %. The principal outcome measure is time to revision surgery,
defined as removal or exchange of at least one
single component. Among reasons for revision,
septic loosening represents 6.3 % of all possible
causes. This is not such a high percentage, but
septic loosening often has the worst outcome for
the patient.

To achieve this aim, only uncemented total hip arthroplasties implanted in the period from january
2000 to december 2013 in primary coxarthrosis and
coxarthrosis secondary to developmental dysplasia
were considered due to a possible bias related to
the presence of antibiotic in the cement. The final
dataset is presented in
Table 1.
Possible risk factors for sepsis are not equally distributed among the four groups, so the Cox proportional hazard method was applied, with revision of
total hip arthroplasty (THA) for septic loosening as
the end point.

Results
The analysis showed that age at surgery and body
mass index (BMI) do not influence septic loosening, while type of articular coupling and gender
do. More specifically, CoC coupling reduces significantly the risk of septic failure compared with
MoM with a hazard ratio of 3.1 (1.6–6.2). CoC

does not influence the risk compared with CoP or
MoP. Women have approximately half the risk of
men ( Table 2).

Barbara Bordini, senior statistician of the Register, has a statistics degree from the University
of Bologna. Since 1999, she has been working
at the Istituto Ortopedico Rizzoli, at the Medical
Technology Laboratory. She is responsible for the
statistical analysis of the Register of Prosthetic
Orthopedic Implants (RIPO). She identifies groups
of patients to start on clinical experiments also
by surveying the regional and local data banks.

The results are unchanged when only late infections
(revision surgery after at least 60 days from implant)
are considered.

Conclusions
It can be concluded that articulation without metal components reduce the risk of precocious amd
late septic failure of THA, although significance was
only reached in comparison with MoM. Male gender shows a higher risk for septic loosening compared with female gender. A limitation of this study
is that comorbidities that may affect the outcome of
sepsis were not considered.

Acknowledgements: All surgeons of orthopedic units in the Region
Emilia Romagna are gratefully acknowledged for sending their data to
the register.

References
1. RIPO annual report, https://ripo.cineca.it, last downloaded February 15,
2015

Corresponding Author:
Barbara Bordini
Statistician
RIPO Register c/o Medical Technology Laboratory,
Istituto Ortopedico Rizzoli
Via di Barbiano 1/10
40136 Bologna (Italy)
E-mail: barbara.bordini@ior.it

AWARD

Pauwels Commemorative Medal 2014
Werner Zimmerli, MD, was awarded the Pauwels commemorative medal by the German Society for
Orthopedics and Orthopedic Surgery (DGOOC). His lecture during the award ceremony was entitled:
"Orthopedic Prosthetic Joint Infections: Pathogenesis und Therapy".
Zimmerli is a well-known infectious diseases specialist with more than thirty years working experience
in the field of internal medicine and infectious diseases. Since 1979 his research focus has been on the
pathophysiology and treatment of implant infections. A major breakthrough in the treatment of these
infections was the proof of rifampicin´s effectiveness against biofilm infections. Working together with
the orthopedist Peter Ochsner and the infection specialist Andrej Trampuz he developed a treatment
algorithm for prosthetic-joint infections [1].
Zimmerli was also a member of the commission of the Infectious Diseases Society of America (IDSA), that published guidelines
for the diagnosis and treatment of prosthetic joint infections. These are based on the published treatment algorithm and have
since become the international standard.
Since retiring as a medical chief physician Zimmerli has been working as a medical consultant for orthopedic infections at the
Kantonsspital Liestal, Switzerland.
He is a advisory board member of the Pro-Implant Foundation and teaches in the foundation´s workshops (https://www.pro-
implant-foundation.org/en/about/who-we-are).
Reference: 1. Zimmerli W, Trampuz A, Ochsner PE. Prosthetic-Joint Infections. N Engl J Med 2004;351:1645-1654

CeraNews 1/ 2015

MATERIALS RESEARCH

The Effect of Chromia Content on Hardness of
Zirconia Platelet Toughened Alumina Composites

Kuntz M
CeramTec GmbH, Plochingen, Germany

Biolox®delta is a zirconia toughened alumina ceramic (ZTA) for biomedical applications. The
success of this material relies on its extraordinary combination of material properties such as
strength, toughness, hardness and biocompatibility. The composition of Biolox®delta includes
SrO, Y2O3, and Cr2O3. Strontia is added for the formation of platelets inside the matrix, which
support the toughness of the material. Yttria is added in order to control the transformation
mechanism of the zirconia phase.

According to Burger et al., it was previously stated that the addition of chromia leads to improved hardness in a ZTA material [1]. However, later studies on this subject reveal a measurable increase in hardness only at a chromia content much higher than is present in Biolox®delta [2]. Further scientific literature suggests that the addition of chromia within a limited range
does not influence the hardness of a ZTA material [3]. CeramTec undertook a comprehensive investigation in order to isolate the impact, if any, of chromia on hardness in Biolox®delta. The results of this analysis are described here.

Description of tests and results
A test series of 4 ZTA variants with different chromia
content was produced in the CeramTec laboratory.
The chromia content in Biolox®delta , as a reference,
is 0.32%. For comparison, samples with lower and
higher chromia content and even 0 % chromia have
been produced. Manufacturing conditions like milling, pressing, sintering and hard machining for all
specimens are identical. The ceramic microstructure, i. e., grain size and grain distribution of the
material components alumina, zirconia, and platelets, are within the normal range. As an example,
Figure 1 shows the microstructure of a speci-

men with 0 % chromia content versus Biolox®delta reference.
Hardness of ceramics is usually measured using the
Vickers 4-sided diamond pyramid. Today the use of
a test load of HV 1, or Hardness Vickers load balance
of 1 kg (=9.8 N), is recommended. In the past, several studies also used other test loads like HV 0.5 or
HV 10. It was thus decided to include these 3 load
levels in this study.
Furthermore, the preferred unit of hardness values
has been changed over time. Today, using the ratio
of load versus projected imprint area for the hard-

CeraNews 1/ 2015

ness value is recommended, which makes gigapascal [GPa] the relevant unit. In historic data, a unitless number was preferred. Such numbers can be
directly compared using the factor 0.009807. As
an example, a hardness value of 2000 [-] equals
19.61 GPa.

HV10

18.0

17.5

17.0

16.5

Influence of test load and strontia

HV0.5

0.14
0.32
chromia content (%)
HV1

0.50

HV10

19.0

18.5
Vickers Hardness (GPa)

These results demonstrate that the presence or
non-presence of chromia in a ZTA material that is
otherwise identical to Biolox®delta has no influence on the hardness of the material, at least in
the range of the amount of chromia investigated
here (0–0.5 % by weight). For the study of Burger
et al., the load level HV 0.5 was used which is not
recommended today [1]. This may be one source of
inaccurate results due to high measurement uncertainty. In addition, the sample in [1] that contained
chromia, also contained SrO, which was absent
from the chromia-free sample. Unfortunately, the
result of the study [1] from 2001 has often been
cited in publications referring to the material profile
of Biolox®delta. However, the statistically substantiated test results discussed here demonstrate that
the chromia content of Biolox®delta does not measurably influence the hardness. ■

HV1

18.5
Vickers Hardness (GPa)

Figure 2 shows the results of the analysis. Mean
values ±1 x standard deviation with the error bar are
plotted. As already well known, the hardness values
are higher at lower load levels of the indentation
(at least within the load range of this study). For all
load levels, no measureable influence of the chromia content to hardness is found. For the reference
hardness value HV1, all results are virtually identical.

HV0.5
19.0

18.0

17.5

17.0

16.5

0.14
0.32
chromia content (%)

0.50

Figure 2: Results of the hardness measurements of the 4 variants
References
1. Burger W, Richter HG, High Strength and Toughness Alumina Matrix Composites by Transformation Toughening and „In Situ“ Platelet Reinforcement (ZPTA) – the New Generation of Bioceramics, Key Engineering Materials 2001;191-195:545–548
2. Bradt RC, Cr2O3 Solid Solution Hardening of Al2O3, Journal of the American Ceramic Society 1967;50:54–55
3. Magnani G, Brillante A, Effect of the composition and sintering process
on mechanical properties and residual stresses in zirconia alumina composites, Journal of the European Ceramic Society 2005; 25:3383-3392
4. ISO 14705 Fine ceramics (advanced ceramics, advanced technical ceramics) – Test method for hardness of monolithic ceramics at room temperature

Corresponding Author:
Meinhard Kuntz PhD
(Manager Oxide Development)
CeramTec GmbH
CeramTec-Platz 1–9
D-73207 Plochingen (Germany)
E-mail: m.kuntz@ceramtec.de

CeraNews 1/ 2015

SCIENCE REPORT

What's New in Endoprosthetics in Russia?
8th Vreden's Readings Conference, St. Petersburg, Russia

Tikhilov RM1, Shubnyakov II1, Atzrodt V2
Research Institute for Traumatology and Orthopedics R.R. Vreden, St. Petersburg, Russia;
CeramTec GmbH, Plochingen, Germany

1
2

In recent years, the "Vreden's Readings" conference has developed into an excellent forum for
Russian orthopedics, and the number of participants from abroad grows year by year. Approximately 800 orthopedists from various regions of Russia and numerous visitors from 29 countries, among them the USA, France, Germany, Italy, Great Britain, Austria and Japan, took part
in the eighth conference. The Eastern European states were represented by specialists from
Lithuania, Latvia, the Ukraine, Belarus, and Kazakhstan.

On three days, 102 scientific presentations and six
lectures were held on the subject of endoprosthetic
replacements of the large joints. The lectures were
delivered in Russian and English and simultaneously
translated. The conference was accompanied by an
exhibition by the 60 leading enterprises in the medical technology industry. Numerous workshops were
devoted to the newest methods in endoprosthetics
and to the conservative treatment of pathologies of
the locomotor system.
The topics with which Russian specialists and experts
are currently dealing in the field of endoprosthetics
are also the main focus of orthopedics worldwide:
• complex revision surgery,
• the therapy of infection-related complications,
• highly complex pathologies of the large joints,

9th Vreden's Readings Conference 2015:
8–10 October 2015, St. Petersburg, Russia
This year's conference will take place in St. Petersburg from the 8th to
the 10th of October. One topic of the scientific program will be periprosthetic joint infection (PJI).The infection expert Prof. Andrej Trampuz,
Charité Berlin (https://www.pro-implant-foundation.org/en/) will organize the PJI session with German and Russian experts, who will present
and discuss the modern concepts of prevention, diagnosis, and therapy.
The subject area foot surgery will be included in the scientific program for
the first time. The results of the conference will be published and made
accessible to all interested persons (congress link http://www.vredenreadings.org/eng/program.php)
We invite you to a stimulating conference with interesting encounters.

R.M. Tikhilov, MD

CeraNews 1/ 2015

• the optimization of care of young and active patients
• and issues of safety and quality in endoprosthetics.
Russian orthopedists are also confronted with specific problems regarding the treatment of frequently occurring dysplasias in certain regions ( case
report), above all in the southern regions of Russia, and the traditionally determined preference for
classical solutions (e.g., osteotomy rather than endoprosthesis).

Focus: Basic and advanced training
The rapid development of endoprosthetics in Russia, with an average yearly growth of 15–20 %, in
some regions even 40–50 %, must be accompanied by rigorous schooling and advanced training
of orthopedic surgeons. The conference made clear
that continuous basic and advanced training are of
particular importance for the professional competence of the operating surgeon, for results analysis,
and for the comprehensive assurance of rehabilitation, without which high-quality results cannot be
achieved.
During the conference, attention was focused in
particular on implant pathologies and implant allergies and on the role played by implant materials and designs in adverse reactions to abrasion
and corrosion products. It became apparent that
the problems in their complexity can be solved only
on a multidisciplinary basis, and that the experts in
the specialized disciplines must join forces to meet
this challenge. As a result of an interesting discussion about contributions by Russian and German
experts it was agreed to carry out further studies
together.

Some of the contributions to the "Vreden's Readings" conference 2014 were published in the journal
Traumatology and Orthopedics of Russia (issues 3
and 4, 2014, Russian and English) and can be downloaded (http://journal.rniito.org/num_en.html).

References
1. Krenn V, Thomas P, Thomsen M, Usbeck S, Scheuber L, Boettner F, Rüther
W, Hopf F, Müller S, Krukemeyer MG, Gehrke T, Kendoff D, Tiemann A, Huber M. Implant-associated pathology: an algorithm for identifying particles in histopathologiy synovialis / SLIM diagnostics.Traumatology and
Orthopedics 2014;3:1
2. Thomas P, Thomsen M, Krenn V, Summer B. Patients with suspected metal implant allergy: Potential clinical pictures and allergological diagnostic
approach (review). Traumatology and Orthopedics 2014;3:142–146

3. Thomsen M, Krenn V, Thomas P, Kretzer JP. Clinical cases of patients with
arthroplasty and heightened blood concentration of metal ions.Traumatology and Orthopedics 2014;4:85–89

Contributions on the
subjects of implant allergies, implant pathologies
and hip revision can be
accessed here in Russian
and in English with the
QR code.

Corresponding Author:
Raschid M. Thikhilov, MD
R. R. Vreden Russian Research Institute of
Traumatology and Orthopaedics
Acad. Baikov Str. 8
195427 St. Petersburg (Russia)
E-mail: info@rniito.org

CASE REPORT
Treatment of dysplastic coxarthrosis
Diagnosis
A 47-year-old female patient with left-sided dysplastic coxarthrosis (Fig. 1) had been treated conservatively during her childhood. This involved retention with a plaster cast in order to reduce the luxation of the left hip. On admission to the hospital she
complained of pains, reduced leg length, and restricted mobility in her left hip joint. The patient was
barely able to walk due to the one-sided leg length
difference (3 cm) and the flexion contraction in the
hip joint. She had a pronounced limp and required a
walking aid. In addition, there was pain in the area
of the lumbar spine.

Therapy

tient's age and her activity demands a ceramic-ceramic bearing was used. Reconstruction of the cup
was done with autologous bone material
(Fig. 1).
It was decided not to perform a complete leglength equalization due to the existing changes in
the lumbar spine. The resulting leg-length difference was 0.8 cm
(Fig. 1). The Harris Hip Score had
improved from 38 to 92 points at the time of the
most recent follow-up examination.
Two years following the operation the cup and
the stem are stable, and no postoperative complications are detectable. The flexion contraction has improved significantly. The patient can walk normally,
requires no walking aid, and is satisfied with the result. ■

The left hip joint was replaced with a cement-free
endoprosthesis via lateral access. Because of the pa-

Figure 1: Female patient with dysplastic coxarthrosis Crowe II, from left to right: preoperative X-ray image, postoperative X-ray image, X-ray image 2 years postoperatively (© Tikhilov)

CeraNews 1/ 2015

SCIENCE REPORT

Tribology: Science and Practice in Korea
Pick from a Bearing Congress in Seoul (South Korea)

Zimmermann M, Graessel M
CeramTec GmbH, Plochingen, Germany

Although total hip arthroplasty (THA) is a very successful type of surgery, it is well-recognized
that clinical outcomes are influenced, among other factors, by the quality of the implants used.
In particular, the choice of materials for the bearing couple plays an important role. In order to
provide the latest updates in this regard, Jun-Dong Chang, MD, Chairman of Department of Orthopaedic Surgery and Director of Arthroplasty Center of Hallym University Dongtan Sacred
Hospital, Seoul (South Korea), organized a full-day congress dedicated specifically to "Tribology: Science and Practice". The event was held at his hospital and was attended by more than
150 Korean surgeons. Eight international faculty members from Germany, Italy, Switzerland,
the USA, China, Japan and India highlighted the meeting with their contributions.

According to Chang, the most important issue in
THA in Korea is to minimize wear and impingement.
Tribology of the bearing surfaces is a topic that continues to be discussed. Therefore, the scientific program of the "Tribology: Science and Practice" congress focused on issues regarding materials, wear
particles, taper corrosion, infection risks related to
bearing surface, current status of bearing surface,
evolution of ceramic bearings, differences between
Asian and Western patients, technical aspects, and
registry.
Given that patients today have a substantially longer life expectancy, it is anticipated that wear-related issues will predominate. Furthermore, it is wellknown that Korean as well as other Asian patients
differ from Western patients in their specific anatomies and lifestyles. Their daily routine requires a particularly large range of motion, and a large proportion of Asian patients are young: Such differences
should be considered as the important issue in arthroplasty in Korea.
Asked about the bearing choice algorithm in Korea,
Chang stated: "All these considerations explain why
the clinical results with conventional polyethylene in
Korean patients were poorer than those in Western
patients. Accordingly, alternative bearing surfaces
have been predominantly used for THA in Korea.
Among the alternative bearing surfaces, MoM, often used for resurfacing, has been associated with
an increased risk of osteolysis, local soft-tissue reactions, tissue and bone necrosis, and potential longterm toxicity. These adverse effects led to a substantial decrease in the use of this kind of hard-on-hard
CeraNews 1/ 2015

bearing surface for hip arthroplasty. This explains
why the use of ceramic bearings has become very
popular in Korea, showing the most reliable results
up to now among Korean patients. Another reason
for the popularity of CoC bearing couples in Korea is the cost-effectiveness with the nationally controlled insurance system."
"Finally, the introduction of Biolox®delta ceramic in
Korea substantially improved the clinical outcomes in
comparison with previous pure alumina ceramic generations, especially regarding breakage and squeaking. This enhanced ceramic also allowed the use of
a large ball head to improve stability and reduce impingement in patients with small sockets, which is
common in Koreans. Breakage of
Biolox®delta is
very rarely reported in Korea, and I have never experienced any fractures of liner or femoral head with
Biolox®delta ceramic." The acceptance of ceramic
bearings in Korea is very high, with an 85,46 % share
of CoC used in primary THA (data on file, South Korea Health Insurance Review and Assessment Service
2014). Thus, clinical outcomes and issues were extensively analyzed and discussed at the meeting. The
Korean situation was reflected in the presentations
by Kyong-Ho Moon, MD, Inha University, Incheon,
and Kyung-Hoi Koo, MD, Seoul National University
Bundang Hospital.

Long-term results of third-generation
CoC bearings in Korea
Moon presented the long-term results with the
third generation of CoC bearings. From April 2001
to January 2008, 349 cementless THA were per-

formed with CoC (Biolox®forte, alumina) bearings
in 331 patients. The patients' mean age at the time
of surgery was 54.6 years (range: 23–87 years). The
most common indication was osteonecrosis, in 191
cases. After a mean follow-up of 8.9 years (range:
6.5–13 years), there was no radiologic evidence of
osteolysis or cup migration. The two main observed
complications were dislocation in nine cases (2.9 %)
and periprosthetic fracture in seven cases (2.2 %).
In three cases (0.9 %) a fracture of the ceramic
component was observed, including one case observed intraoperatively (liner chipping). In five cases
(1.6 %) squeaking occurred, however, without requiring revision. In conclusion, the long-term results
of third-generation CoC bearings in cementless primary THA were excellent.

4. Lee YK, Ha YC, Koo KH. Comparison between 28 mm and 32 mm ceramic-on-ceramic bearings in total hip replacement. Bone Joint J 2014;96–
B(11):1459–63 [Level of Evidence I Study]

Additional Selection of recently published ceramic bearing
r elated papers of Korean Surgeons,

Kang BJ, Ha YC, Ham DW, Hwang SC, Lee YK, Koo KH (2014) Third-generation alumina-on-alumina total hip arthroplasty: 14- to 16-year follow-up study. Oct 2. pii: S0883-5403(14)00729-3. doi: 10.1016/j.
arth.2014.09.020. [Level of Evidence IV]

Kim YH, Park JW, Kim JS (2012) Cementless metaphyseal fitting anatomic
total hip arthroplasty with a ceramic-on-ceramic bearing in patients thirty years of age or younger. J Bone Joint Surg Am 94:1570–1575 [Level of
Evidence IV]

Kim Y, Kim YH, Hwang KT, Choi IY (2014) Isolated acetabular revision
with ceramic-on-ceramic bearings using a ceramic head with a metal
sleeve. J Arthroplasty online accepted manuscript [Level of Evidence IV]

Lee YK, Ha YC, Koo KH (2014) Comparison between 28-mm and 32-mm
ceramic-on-ceramic bearings in total hip replacement. Bone Joint J 96B:1459–1463 [Level of Evidence I]

Koo reported on the retrospective findings from several cohorts of patients all treated with CoC bearings but with different stem and cup systems [1, 2,
3] (Level of Evidence III and IV).

Park YS, Moon YW, Lee KH, Lim SJ (2014) Revision hip arthroplasty in patients with a previous total hip replacement for osteonecrosis of the femoral head. Orthopedics Dec; 37(12):e1058-62. doi: 10.3928/0147744720141124-51 [Level of Evidence IV]

Shin YS, Han SB, Jung TW (2014) Comparison between preassembled and
modular cups in primary cementless total hip arthroplasty: a two-year
minimum follow-up study. J Arthroplasty 10 [Level of Evidence II]

Yoo JJ, Yoon PW, Lee YK, Koo KH, Yoon KS, Kim HJ (2013) Revision total
hip arthroplasty using an alumina-on-alumina bearing surface in patients
with osteolysis. J Arthroplasty 28:132–138 [Level of Evidence IV]

Between 1998 and 2008, he used the Biolox®forte
ceramic and since March 2008 he is using Biolox®
delta. The lessons learned from 10 years’ experience with the third generation of ceramic articulation are that we should
• not use sandwich-type ceramic liners,
• not use 28-mm-short neck heads,
• not use metal shells with an elevated rim, and finally,
• we should inform the patients not to squat.

Yoon HJ, Yoo JJ, Yoon KS, Koo KH, Kim HJ (2012) Alumina-on-alumina
THA performed in patients younger than 30 years: a 10-year minimum
follow-up study. Clin Orthop Relat Res 470:3530–3536 [Level of Evidence IV]

Delta ceramic bearing: Will it guarantee
better results?

Between March 2008 and September 2011, 570
Biolox®delta CoC hips were implanted in 492 patients. The mean age of the patients at surgery was
50 years (range: 16–83 years), with osteonecrosis
being the main reason for surgery in 311 cases. After a mean follow-up of 42 months, neither osteolysis nor wear has been observed. The only case
of ceramic liner fracture was due to intraoperative
malpositioning of the liner. The use of ceramic ball
heads 32 mm or 36 mm in diameter clearly reduced
the risk of dislocation compared with 2
8-mm ball
heads [4] (Level of Evidence I). ■

Corresponding Authors:
Martin Zimmermann PhD
(Senior Scientific Consultant)
Matthias Grässel MSc
(Regional Manager Asia)
CeramTec GmbH
CeramTec-Platz 1–9
D-73207 Plochingen (Germany)
E-mail: m.zimmermann@ceramtec.de
E-mail: m.graessel@ceramtec.de

References
1. Ha YC, Koo KH, Jeong ST, Joon Yoo J, Kim YM, Joong Kim H. Cementless
alumina-on-alumina total hip arthroplasty in patients younger than 50
years: a 5-year minimum follow-up study. J Arthroplasty 2007;22:184–8
[Level of Evidence IV study]
2. Ha YC, Kim SY, Kim HJ, Yoo JJ, Koo KH. Ceramic liner fracture after cementless alumina-on-alumina total hip arthroplasty. Clin Orthop Relat
Res 2007;458:106–10 [Level of Evidence III study]
3. Koo KH, Ha YC, Jung WH, Kim SR, Yoo JJ, Kim HJ. Isolated fracture of the
ceramic head after third-generation alumina-on-alumina total hip arthroplasty. J Bone Joint Surg Am 2008;90:329–36 [Level of Evidence III
study]

CeraNews 1/ 2015

NEWS TICKER

Heinz-Mittelmeier Research Award for Study on
Ceramic Implant Applications in Arthroplasty

Daniel MacDonald, Research Associate of the Implant Research Center at Drexel University’s
School of Biomedical Engineering, Science, and Health Systems, Philadelphia, USA, was awarded the Heinz Mittelmeier Research Award 2014. The award, which is endowed with 5,000 Euros,
was presented by Fritz-Uwe Niethard, MD, at the German Congress of Orthopaedics and Traumatology (DKOU) on 29. October 2014. McDonald is specialized in analyzing implant performance
and material degradation in artificial hip and knee joints under clinically relevant conditions. He
has investigated the role of ceramic materials in reducing the amount of corrosion observed in
modular junctions in total hip arthroplasty and received the honor for his study entitled "What
Factors Influence Fretting Corrosion in Total Hip Arthroplasty with Ceramic Heads?"

ABSTRACT

Figure 1: Heinz-Mittelmeier Scientific Award laureate 2014
Daniel MacDonald, Philadelphia, USA, presenting his results
at DKOU 2014 in Berlin (© Starface)

Corrosion at the femoral head-stem taper interface
has recently re-emerged as a clinical concern in total hip arthroplasty. In severe cases, the metal debris
and metal ions released can cause adverse tissue reactions, even with MoP components. Prior studies
regarding head-neck taper corrosion were based
largely on cobalt-chrome alloy femoral ball heads.
Less is known about taper corrosion with ceramic
femoral ball heads.
Our research group recently conducted several retrieval studies to investigate the role ceramics play
in taper corrosion. We asked
• whether ceramic ball heads result in less taper
corrosion than CoCr ball heads;
• what device and patient factors influence taper
fretting corrosion;
CeraNews 1/ 2015

• whether the mechanism of taper fretting corrosion in ceramic ball heads differs from that in
CoCr heads;
• what is the difference in taper angle clearance
and contact location between ceramic and CoCr
ball heads;
• does taper angle clearance influence the severity
of fretting corrosion;
• what is the prevalence of fretting corrosion in retrieved adaptor sleeves; and
• what device and patient factors influence the
sleeve fretting corrosion?
Since 2000, we have retrieved more than 3,000
THA components from revision surgery as part of
a multi-institutional, IRB approved retrieval program. From these, 50 ceramic femoral head-stem
pairs were matched with 50 CoCr femoral headstem pairs based on implantation time, lateral offset, stem design, and flexural rigidity. Additionally,
we analyzed 35 titanium sleeves that were used in
conjunction with a ceramic femoral head. All of the
components were inspected for evidence of fretting and corrosion using a visual scoring technique
based on severity and extent. Taper angle and clearance were assessed using a high-resolution roundness machine.

Predictors: stem alloy and flexural rigidity
Fretting and corrosion scores were lower for the
stems in the ceramic ball head cohort. We observed dark corrosion deposits outside the head-

neck taper junctions in three of 50 (6 %) of the
MoM taper cohort and zero of 50 (0%) of the
CoM taper cohort. Stem alloy and flexural rigidity were predictors for stem corrosion damage. Taper angle clearance was not a predictor of corrosion scores. The corrosion mechanism was similar
in both cohorts, although for ceramic ball heads
only the metal stem was engaged in the corrosive
process. For the sleeved ceramic ball heads, moderate to severe fretting-corrosion scores (score ≥2)
were common, and were observed in 97 % (34/35)
of internal tapers. These scores were similar to levels observed in prior studies of tapers in CoCr ball
heads. However, it is generally accepted that titanium debris is less biologically active than cobalt or
chromium debris.

New focus beyond wear and tribology
Fretting-initiated crevice corrosion observed in tapers is a complex problem, and the severity depends on multiple factors. Retrieval studies that
isolate variables in devices and patients can be designed to identify device and patient factors that
aggravate or mitigate corrosion damage at the taper interfaces. We hypothesized that ceramic femoral ball heads, which are electrical insulators, would
lead to lower stem taper corrosion than previously
reported with CoCr femoral heads; indeed, this ap-

Daniel W. McDonald, Master of Science, earned his Bachelor of Science
in 2006 and his MS in 2010, both from Drexel University in biomedical
engineering with a focus on biomechanics.
He currently serves as a Research Associate of the Implant Research Center at Drexel University’s School of Biomedical Engineering, Science, and
Health Systems where he manages an orthopedic implant retrieval program. He is responsible for the data collection, analysis, and verification
of multiple large-scale studies investigating the in-vivo performance of orthopedic biomaterials, as a ssessed through human retrieval specimens.
His involvement in retrieval analysis has been instrumental in understanding the performance of various orthopedic device designs and materials.
Specifically, McDonald has investigated the factors that can mitigate the
in-vivo degradation of polymeric and metallic biomaterials used in total
hip and knee arthroplasty. His expertise and analysis of retrieved orthopedic devices have been presented at international conferences and workshops.

pears to be the case. Despite prior suggestions that
taper angle clearance would influence the behavior of fretting corrosion, we observed no evidence
in either cohort to support this claim. The results
of these studies suggest that there could potentially be a new focus in ceramic component research
in hip arthroplasty, beyond wear and tribology, to
better understand the role of ceramics in mitigating
modular taper corrosion. ■

Heinz-Mittelmeier Research Award 2015
The German Society for Orthopaedics and Orthopaedic Surgery e.V.
(DGOOC) presents the 5,000-Euro Heinz-Mittelmeier Research Award
in collaboration with CeramTec GmbH each year. The award is offered to young doctors, engineers, and scientists aged 40 and under
for outstanding research and development work in the field of bioceramics and the problem of wear in joint replacements, and in combination with clinical results of ceramic implants.
Work may be published in scientific journals or in book form. Unpublished manuscripts that are intended for publication or have already
been submitted for publication are also accepted, along with graduate theses, dissertations, and
post-doctoral dissertations. Only work that has already received a similar award is excluded from the
competition.
The winner is chosen by a DGOOC jury. The 2015 research award will be presented during the congress jointly sponsored by the DGOOC, the German Association for Trauma Surgery (DGU), and the
Professional Association of Orthopaedists and Trauma Surgeons (BVOU), from October 20 to 23,
2015 in Berlin.
How to participate
To participate in the competition send your work in German or English by July 31, 2015, with a corresponding declaration that it has not been distinguished with a similar award, solely via email to:
info@dgooc.de.

CeraNews 1/ 2015

NEWS TICKER

34th Annual Meeting of the European
Bone and Joint Infection Society
Estoril, Portugal
10–12 September 2015
Information and online registration:
http://www.ebjis2015.org/

36th SICOT Orthopaedic World Congress
Société Internationale de Chirurgie Orthopédique et
de Traumatologie
Guangzhou, China
17–19 September 2015
Information and online registration:
http://www.sicot.org/guangzhou

International Society for
Technology in Arthroplasty
ISTA Congress 2015
Vienna, Austria
30 September to 3 October 2015
Information and online registration:
http://www.istaonline.org/?page_id=3139

Vreden‘s Readings
9th Annual Conference
Saint Petersburg, Russia
8–10 October 2015
Information and online registration:
http://vredenreadings.org/eng/program.php

CeraNews 1/ 2015

This educational Congress will focus on:
• Economical impact of the "Septic Patient" – How to prevent costs?
• Quality Management for Septic Surgery – Is there an European Approach?
• Diagnostic tools in MSK infections
• Revision Surgery in infected joint replacement
The Scientific Program will include overviews, state of the art lectures, and
controversial debates. Outstanding faculty members will present both pro
and con positions while further challenging and exploring the optimal
treatment for patients, with emphasis on the appropriate use of new and
emerging treatment options. The previous congress, held in Utrecht, The
Netherlands, established a new record with more than 600 participants.
This will be first time that the SICOT Orthopaedic World Congress will be
held in mainland China. The congress will lay down the blueprints for important issues of today’ s orthopaedic development and address our role
in re-evaluating current controversies in orthopaedics, as congress president Guixing Qiu says. He expects in-depth discussions covering all orthopaedic subspecialties, enhancing international academic exchange.
Numerous instructional courses will be held for young surgeons and trainees from China and all over the world.
ISTA’ s annual meeting has become the hub where comprehensive analysis of the past, present and future of joint replacement technology and
related science is presented. It is where the most extensive and engaging
scientific discussions occur between orthopaedic surgeons, scientists and
engineers from academia and industry. Atypical of other meetings, ample
time is given for such discussions in both podium papers and e-posters.
Interaction of this kind facilitates good education and inspires technological innovation. Theme of this years´ congress is "Innovation Meets Classic".
The conference is organized by R.R. Vreden Russian Scientific
Research Institute of
Traumatology and Orthopedics. This year´s
scientific program focusses on the current
status of the arthroplasty in Russia and its particular challenges, such as
• surgical activity: quality versus quantity
• modern "premium" implants versus budget implants
• arthroplasty registers: new aspects
• economic aspects and ways to optimize the m
anagement in the joint
arthroplasty.
Various aspects of arthroplasty of hip, Knee, shoulder joint, and ankle
will be discussed as well as arthroscopic techniques and bone oncology.
Solutions for reactions to the implant and current concepts in the periprosthetic infection are further subjects of the conference.

Initiative for Quality and Safety –
Endoprothetik 2015
Congress of the Arbeitsgemeinschaft Endoprothetik GmbH
Frankfurt/Main, Germany
05–06 November 2015
Information and online registration:
http://www.ae-gmbh.com/ae-veranstaltungen/
ae-kongresse/eventeinzelheiten/82/-/kongress-qualitaets-und-sicherheitsinitiative-endoprothetik-2015-frankfurt-main-05-06-11-2015

The subject of safety and quality in endoprosthetics is still being discussed
publicly. The focus is on implant failure, material intolerances, and taper
and wear issues.
The conference was conceived by physicians, representatives of the medical technology industry, engineers, and basic researchers to present and
debate the strengths, weaknesses and boundaries of endoprosthetics.
Case presentations will be discussed, as will appropriate communication
with the patient in case of adverse events, or the legally correct way to
deal with incidents and failure analyses.
The limits of biomechanical tests and the influence of combination implants that have not been tested together will be examined. The economization of medicine in general, and specifically in the field of endoprosthetics, is to be considered.
Last but not least, the informative value of joint registers and patient-oriented quality standards will be addressed.

British Hip Society and Società Italiana Dell´ Anca
Milan, Italy
26–27 November 2015
Information and online registration:
www.sidabhs-jointhip.com

Pro-Implant Foundation – Educational
Plattform
Information:
https://www.pro-implant-foundation.org/en/
education/publications
Short video on biofilms:
https://www.pro-implant-foundation.org/en/
education/general-information

The British Hip Society and the Società Italiana dell’Anca will hold their
first combined meeting. It will be the very first time that two distinguished national speciality societies have integrated to organize a joint
congress that will combine their traditions, current practices, and future
clinical and research trajectories.
By sharing experiences in both primary and revision hip arthroplasty, discussing different techniques (bony fixation, tribology, and more), examining the results of hip preserving surgery and arthroscopy, or simply considering e verything about the hip, it will be a unique opportunity
to improve surgical skills and understand current state of the art clinical
practice.
The web page of the
Pro-Implant Foundation offers useful
publications, guidelines, and poster/presentations on bone
and joint infections.
By watching the video entitled "Formation
of Biofilm on Implant
Surface" you can learn
more about the role of biofilms in prosthetic joint infection. The foundation is a non-profit organization of the german civil right and dedicated
to supporting research, education, global networking, and care of patients with bone, joint or implant infection. The aim of the foundation is
to improve the quality of patient lives.

International combined Meeting

CeraNews 1/ 2015

NEWS TICKER

Clinical Management
Thomas P, Stea S
Metal Implant Allergy and Immuno-Allergological
Compatibility Aspects of Ceramic Materials

This pocket guide presents background information and ways to proceed in patients
when an implant allergy is suspected as diagnostic criteria of hypersensitivity to metal implants are inconclusive. To rule out other diagnoses, an orthopedic examination has to
take place.
For the first time, a clinical algorithm has
been developed for procedures in clinical
practice for when an implant allergy is suspected. The algorithm is presented as a laminated loose insert. The flow chart contains
additional information on the histopathological particle algorithm, according to Krenn.
Clinical Management of Joint Arthroplasty

In addition, it also addresses medical practitioners and scientists of adjacent specialist disciplines who are not confronted on a daily basis with problems regarding
endoprosthetics but, when required, would like to access important information
on a specific topic.
Metal Implant Allergy

The pocket guide is one of a series, written for orthopaedic surgeons who seek
help in how to proceed when implant patients suffer from allergic reactions to any
metal implant particle such as nickel, cobalt, or chromium or to bone cement. An
algorithm is being provided as a loose insert which is laminated.

32 pages, 15,5 x 23,5 cm
First Edition 2015
Springer-Verlag Berlin Heidelberg 2015
Print (Softcover): ISBN 978-3-662-47439-6
E-book: ISBN 978-3-662-47440-2

Clinical Management of Joint Arthroplasty

The volumes of the Clinical Management Guide series are directed at orthopaedic
surgeons who want to acquire information rapidly while saving as much time as
possible. As a helpful advisory tool, this Pocket Guide concisely and clearly imparts
the current state of knowledge on selected issues of everyday clinical practice and,
in doing so, concentrates purely on the essential.

Peter Thomas · Susanna Stea

Metal Implant
Allergy and ImmunoAllergological
Compatibility Aspects
of Ceramic Materials

isbn 978-0-000-00000-2

Date of Publication: June 2015

Clinical Management
Walter W et al.
Practical Guide for Handling Noises in Hard-on-Hard Bearings
22 pages, 15,5 x 23,5 cm
First Edition 2015
Springer-Verlag Berlin Heidelberg 2015
Print (Softcover): ISBN 978-3-662-46026-9
E-book: ISBN 978-3-662-46027-6
Date of Publication: May 2015

Biolox® Inside App

Download
Get the Biolox® App for your Smartphone or Tablet.
The Biolox® Inside app (33MB) is available for iOS
(5.1.1 or higher) devices like the iPad and iPhone
free of charge in the Apple App Store.

The Biolox® Inside app (23MB) is also available for
Android tablets und smartphones (2.2 or higher).

780000 000002

This book provides recommendations and a
clinical algorithm for the assessment of noise
in total hip arthroplasties with hard-on-hard
bearings. It covers all aspects from diagnostics to therapy and adequate management,
as well as monitoring, possible prevention,
and patient information.
• Current thinking and scientific knowledge
regarding noises including squeaking in
hard-on-hard bearings
• Clinical algorithm on how to treat a patient with noisy THRs
• Case reports.
What must be taken into
consideration when handling
and implanting ceramic components? Which wear couple
can be used in the rare event
of a ceramic fracture? You
will find answers to these
questions and more information within the new Biolox®
Inside app which lets you access information on Biolox®
implants quickly from anywhere.
Based on live surgeries, 3-D animations, and literature reviews, Biolox®
Inside compiles the current knowledge about the use of ceramics in orthopedics. Originally developed with orthopedic surgeons for orthopedic surgeons, practitioners of all levels and specialties, the app is a condensed reference and educational tool.
With the Biolox® motion capture mode, track the ceramic joint replacement in three dimensions and identify the joint angle and position in
different motion patterns.
By being a comprehensive reference, this is your must-have app for
quick review on the wards, or at home.

Apple, the Apple logo, iPhone and iPad are trademarks of Apple Inc. registered in the U.S. and other countries. Android is a trademark of Google Inc..

CeraNews 1/ 2015

Biolox® Inside is organized into sections by joint. Explore the different
sections each containing:
• Clinical and material information
• Features
• Live surgical videos
• Handling
• 3-D animation
• Literature

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